I created a javascript confirm as below.
<script Type="Text/Javascript">
function CheckListBox(lvi)
{
if(lvi == "")
{
if(confirm("Are you sure?"))
{
return true;
}
else
{
return false;
}
}
}
</script>
I need to test if the ListBox.Items control is empty... I already made reference on my aspx page
<script language="javascript" type="text/javascript" src="/JS/confirm.js"></script>
I want to know how to call it on my aspx.cs page . . . So I can pass the parameter:
string oi = Listbox_Clubes.Items.Count.ToString();//Its the parameter I want to pass
See this link for how to execute javascript from code behind
protected void Page_Load(object sender, EventArgs e)
{
ScriptManager.RegisterStartupScript(this, this.GetType(), Guid.NewGuid().ToString(), "CheckListBox(" + Listbox_Clubes.Items.Count.ToString() + ");", false);
}
Note: you must add a ScriptManager control in aspx page.
For your javascript, you can get the value without the code-behind (this assumes the script code is in the same page, in order to get the client ID):
<script>
function ClickListBox() {
if ($("#<%= Listbox_Clubes.ClientID %>").val() === null) {
if (confirm("Are you sure?")) {
return true;
}
else {
return false;
}
}
}
</script>
Similarly, you don't use javascript to validate on the server side. The code you posted will return all items in the ListBox. Here is one way to get the count of the number of selected items (I'm using .ToString() based on the OP code example):
string oi = Listbox_Clubes.Items.Cast<ListItem>().Where(i => i.Selected).Count().ToString();
However, there is no reason why you would get this value and pass it back to the client-side to do validation (what it sounds like you want to do in your post). Mainly because this involves a post-back, and client-side validation, by its nature, should occur before post-back. Also, you will still need to do server-side validation, even when you have client-side validation.
Related: in the code-behind, you can test to see if anything is selected by:
bool hasValue = Listbox_Clubes.SelectedItem != null;
The .SelectedItem returns the selected item with the lowest index in the list control. When nothing is selected, this value is null... so you know if the value isn't null, then at least one item was selected.
If you want to require that they choose at least one item, you can use a RequireFieldValidator and let that handle both validations. If you haven't done much with ASP.NET validators, that would be one good thing to read up on.
It sounds like you probably should read more about client-side validation and server-side validation and how to use them... because it seems like you are mixing them up.
The count code is a modified version of code in ASP:ListBox Get Selected Items - One Liner?
Related
I currently use a hidden input field that is assigned the value of the tab that has just been selected, via javascript, like so:
function onTabSelecting(sender, args) {
var tab = args.get_tab(); //get selected tab
document.getElementById("MainContent_hdnPreviousTab").value = tab.get_text(); //assign value to hidden field
if (tab.get_pageViewID()) { //ignore
tab.set_postBack(false);
}
}
I then use this assigned value when the page is returned to, on client-side (ajax) PageLoad() event:
<script type="text/javascript" language="javascript">
var runOnce = false;
function pageLoad() {
if (!runOnce) {
var lastTab = document.getElementById("<%= hdnPreviousTab.ClientID %>");
if (lastTab.value) {
if (tabStrip) {
var tab = tabStrip.findTabByText(lastTab.value);
if (tab) {
tab.click();
}
}
}
runOnce = true;
}
}
</script>
Currently in IE this works fine (I know right?), the value that was previously set in javascript is still there and i am able to lcoate the tab that the user left the page on. However in FF, Chrome, etc. i have no such luck. The hidden field is returned to it's empty state (value = "") regardless of utilising viewstate or not.
Very curious as to whether anyone has an alternative method that would be appropriate in this situation. Please let me know if this is unclear.
Many thanks.
You could use localstorage.
localStorage.setItem('tab', value);
So I'm putting together a little registration area for my web project, here. The user inputs various strings such as "Username", "Password", etc.
I already have a bit of code set up in order to prevent duplicate Usernames or Passwords in the database. I also have a guard in place if the "Password" and "Repeat Password" fields don't match.
What I'm trying to do now is to -
1: If the user attempts to Submit data while a field is blank, it will not post.
2: Display a "Fields cannot be blank" div I've assigned "display: none" to.
I was thinking something along the lines of assigning the input fields a class of "Required", and using some sort of code such as
if == null
.show;
return false; //To prevent the rest of the function (the submit button posting to login/register) from firing.
Running into obscene problems. Anyway. Here's what I have so far.
$("#SubmitButton").click(function () { //Click Submit
if ($("#PassReg").val() != ($("#PassConfirm").val())) { //Both fields match
$("#PasswordMismatch").show(); //Or this div shows you messed up
return false; //And nothing else fires
}
$.post("login/register", $('#ConfirmPanel *').serialize(), function (result) {
if (result == 2) //Json return from C#
$("#UsernameInUse").show(); //Shows an error div
else if (result == 3) //Json return from C#
$("#EmailInUse").show(); //Shows an error div
else {
$("#ConfirmPanel").dialog('close'); //Closes the registration dialog
}
});
});
Any thoughts? At first I thought that I literally -cannot- use "class" to mark an input field, and then have that input field compared to a null value. I don't know, though.
You should use the .submit() jquery event handler on the form instead of .click() on the button. Then return false to prevent the normal form submission if needed.
Since you are trying to submit the form using $.post you should stop the default behavior of the form submit by alwasy returning false from submit button click handler.
$("#SubmitButton").click(function () { //Click Submit
if ($("#PassReg").val() != ($("#PassConfirm").val())) { //Both fields match
$("#PasswordMismatch").show(); //Or this div shows you messed up
return false; //And nothing else fires
}
$.post("login/register", $('#ConfirmPanel *').serialize(), function (result) {
if (result == 2) //Json return from C#
$("#UsernameInUse").show(); //Shows an error div
else if (result == 3) //Json return from C#
$("#EmailInUse").show(); //Shows an error div
else {
$("#ConfirmPanel").dialog('close'); //Closes the registration dialog
}
});
return false;
});
The jQuery way of preventing form submission is to use preventDefault(), like:
$("#SubmitButton").click(function (event) { //Click Submit
if ($("#PassReg").val() != ($("#PassConfirm").val())) { //Both fields match
$("#PasswordMismatch").show(); //Or this div shows you messed up
event.preventDefault(); //And nothing else fires
return;
}
//...
});
However, since you are posting the form asynchronously when validation passes, what you really want is something more along the lines of:
$("#SubmitButton").click(function (event) { //Click Submit
event.preventDefault(); //we don't ever want to allow the default behavior
if ($("#PassReg").val() != ($("#PassConfirm").val())) { //Both fields match
$("#PasswordMismatch").show(); //Or this div shows you messed up
return;
}
//post the form
});
The rest of what you suggest (using a class to mark each required input field, checking them all for empty strings) is reasonable.
Be aware that because you are binding the button's click event instead of the form's submit event it is entirely possible for the user to submit your form without ever clicking on your button and triggering your validation code. For instance, by pressing return from any one of your text fields.
Also note that in this case you may find it more convenient to just use a traditional onsubmit directive on the form, like:
<form onsubmit="validateAndPost(); return false;">
<!-- inputs and buttons, etc. -->
</form>
<script>
function validateAndPost() {
if ($("#PassReg").val() != ($("#PassConfirm").val())) { //Both fields match
$("#PasswordMismatch").show(); //Or this div shows you messed up
return;
}
//post the form
}
</script>
Example: http://jsfiddle.net/AwxGE/
I admire your desire to use jquery, however I would advise using a normal ASP.NET ReqiredFieldValidator control. As well as making your page substantially more concise and easy to maintain, it also allows you to very simply invoke server-side validation:
public void submitbutton_click(object sender, EventArgs args){
Page.Validate();
if(Page.IsValid){
doStuff();
}
}
Please don't reinvent the wheel, and don't trust the browser to behave as you think it will.
use this -
$(document).on('click', '#SubmitButton', function () {
`enter code here`
});
I have a little problem about using jQuery (I really do not know jQuery but I am forced to use it).
I am using Visual Studio 2008, ASP.NET web app with C#, Telerik controls on my pages. I am also using SqlDataSources (connecting to stored procedures) on my pages
My pages are based on a master and content pages and in content pages I have mutiviews.
In one of the views (inside one of those multiviews) I had made two radcombo boxes for country and city requirement like cascading dropdowns as parent and child combo boxes. I used old way for doing that, I mean I used update panel and in the SelectedIndexChange event of parent RadComboBox (country) I wrote this code:
protected void RadcomboboxCountry_SelectedIndexChanged(object o, RadComboBoxSelectedIndexChangedEventArgs e)
{
hfSelectedCo_ID.Value = RadcomboboxCountry.SelectedValue;
RadcomboboxCity.Items.Clear();
RadcomboboxCity.Items.Add(new RadComboBoxItem(" ...", "5"));
RadcomboboxCity.DataBind();
RadcomboboxCity.SelectedIndex = 0;
}
My child radcombo box can fill by this code, let me tell you how: the child SqlDataSource has a stored procedure that has a parameter and I fill that parameter with this line
hfSelectedCo_ID.Value = RadcbCoNameInInsert.SelectedValue;
RadcbCoNameInInsert.SelectedValue means country ID.
After doing that SelectedIndexChange event of parent RadComboBox (Country) could not be fired therefore I forced to set the AutoPostback property to true.
After doing that, everything was ok until some one told me can you control focus and keydown of your radcombo boxes (when you press the Enter key on the parent combobox [country], so child combobox gets focus -- and when you press upperkey on child radcombobox [city], parent combobox[country] gets the focus - for users that do not want to use mouse for input and choose items).
I told him this is web app, not win form and we can not do that. I googled it and I found jQuery the only way for doing that ... so I started using jQuery. I wrote this code with jQuery for both of them :
<script src="../JQuery/jquery-1.4.1.js" language="javascript" type="text/javascript"></script>
<script type="text/javascript">
$(function() {
$('input[id$=RadcomboboxCountry_Input]').focus();
$('input[id$=RadcomboboxCountry_Input]').select();
$('input[id$=RadcomboboxCountry_Input]').bind('keyup', function(e) {
var code = (e.keyCode ? e.keyCode : e.which);
if (code == 13) { -----------> Enter Key
$('input[id$=RadcomboboxCity_Input]').focus();
$('input[id$=RadcomboboxCity_Input]').select();
}
});
$('input[id$=RadcomboboxCity_Input]').bind('keyup', function(e) {
var code = (e.keyCode ? e.keyCode : e.which);
if (code == 38) { -----------> Upper Key
$('input[id$=RadcomboboxCountry_Input]').focus();
$('input[id$=RadcomboboxCountry_Input]').select();
}
});
});
</script>
This jQuery code worked but autopostback=true of the parent RadComboBox became a problem because when SelectedIndexChange of the parent RadComboBox is fired after that Telerik Skins runs and after that I lost parent combobox focus and we should use mouse but we don't want it....
To fix this problem I decided to set AutoPostback of parent CB to false and convert
protected void RadcomboboxCountry_SelectedIndexChanged(object o, RadComboBoxSelectedIndexChangedEventArgs e)
{
hfSelectedCo_ID.Value = RadcomboboxCountry.SelectedValue;
RadcomboboxCity.Items.Clear();
RadcomboboxCity.Items.Add(new RadComboBoxItem(" ...", "5"));
RadcomboboxCity.DataBind();
RadcomboboxCity.SelectedIndex = 0;
}
to a public non static method without parameters and call it with jQuery like this (I used onclientchanged property of parent combobox like
onclientchanged = "MyMethodForParentCB_InJquery();"
instead of selectedindexchange event):
public void MyMethodForParentCB_InCodeBehind()
{
hfSelectedCo_ID.Value = RadcomboboxCountry.SelectedValue;
RadcomboboxCity.Items.Clear();
RadcomboboxCity.Items.Add(new RadComboBoxItem(" ...", "5"));
RadcomboboxCity.DataBind();
RadcomboboxCity.SelectedIndex = 0;
}
For doing that I read the below manual and do that step by step :
http://www.ajaxprojects.com/ajax/tutorialdetails.php?itemid=732
but this manual is about static methods and this is my new problem ...
When I am using static method like :
public static void MyMethodForParentCB_InCodeBehind()
{
hfSelectedCo_ID.Value = RadcomboboxCountry.SelectedValue;
RadcomboboxCity.Items.Clear();
RadcomboboxCity.Items.Add(new RadComboBoxItem(" ...", "5"));
RadcomboboxCity.DataBind();
RadcomboboxCity.SelectedIndex = 0;
}
I got some errors and this method could not recognize my controls and hidden field...
One of those errors:
Error 2 An object reference is required for the non-static field, method, or property 'Darman.SuperAdmin.Users.hfSelectedCo_ID' C:\Javad\Copy of Darman 6\Darman\SuperAdmin\Users.aspx.cs 231 13 Darman
Any idea or is there any way to call non static methods with jQuery?
(I know we can not do that but is there another way to solve my problem?)
Your problem is related to the interaction between .NET and jQuery. Basically, if you change values in the user interface using jQuery, .NET doesn't know anything about it. If you make an ajax call using jQuery, it doesn't know anything about .NET's controls.
The ajax method you found and started to implement is the right way to go. However, jQuery is going to make a true ajax call. Everything you do in code behind has to exist in that static function. It can create objects and do things with them, but no controls will exist when you enter this function at runtime (unlike using an updatepanel, which walks through the full page lifecycle).
So, something like this is not going to work:
public static void MyMethodForParentCB_InCodeBehind()
{
hfSelectedCo_ID.Value = RadcomboboxCountry.SelectedValue;
RadcomboboxCity.Items.Clear();
RadcomboboxCity.Items.Add(new RadComboBoxItem(" ...", "5"));
RadcomboboxCity.DataBind();
RadcomboboxCity.SelectedIndex = 0;
}
In the case above, you don't have access to any of the controls, so you're basically left with populating the control yourself using jQuery.
You'll need to send the selected value to the static method, create the new list item as a string, and return this to the ajax callback. Within the jQuery ajax callback you'll have to add the item into the list yourself.
public static string MyMethodForParentCB_InCodeBehind( string selectedvalue )
{
string rtrnString = SomeClass.GetValue( selectedvalue );
return rtrnString;
}
The following function in your presentation logic should retrieve this result and add it to your list using jQuery.
function AjaxSucceeded (result)
{
alert(result.d);
// result.d will have the value of the string passed back from the function
// it's up to you to populate the combobox using jQuery.
}
The side effect of doing this is that the .NET control no longer shares the same viewstate that it did before. Meaning, if the page does a postback, the new value entered into your combobox will not be available in codebehind. You most likely won't even get this far as you'll probably get view state errors.
You're kind of in a tough spot. You might want to look into using updatepanels, as you will have access to the controls in code behind.
I am having what I believe should be a fairly simple problem, but for the life of me I cannot see my problem. The problem is related to ScriptManager.RegisterStartupScript, something I have used many times before.
The scenario I have is that I have a custom web control that has been inserted into a page. The control (and one or two others) are nested inside an UpdatePanel. They are inserted onto the page onto a PlaceHolder:
<asp:UpdatePanel ID="pnlAjax" runat="server">
<ContentTemplate>
<asp:PlaceHolder ID="placeholder" runat="server">
</asp:PlaceHolder>
...
protected override void OnInit(EventArgs e){
placeholder.Controls.Add(Factory.CreateControl());
base.OnInit(e);
}
This is the only update panel on the page.
The control requires some initial javascript be run for it to work correctly. The control calls:
ScriptManager.RegisterStartupScript(this, GetType(),
Guid.NewGuid().ToString(), script, true);
and I have also tried:
ScriptManager.RegisterStartupScript(Page, Page.GetType(),
Guid.NewGuid().ToString(), script, true);
The problem is that the script runs correctly when the page is first displayed, but does not re-run after a partial postback. I have tried the following:
Calling RegisterStartupScript from CreateChildControls
Calling RegisterStartupScript from OnLoad / OnPreRender
Using different combinations of parameters for the first two parameters (in the example above the Control is Page and Type is GetType(), but I have tried using the control itself, etc).
I have tried using persistent and new ids (not that I believe this should have a major impact either way).
I have used a few breakpoints and so have verified that the Register line is being called correctly.
The only thing I have not tried is using the UpdatePanel itself as the Control and Type, as I do not believe the control should be aware of the update panel (and in any case there does not seem to be a good way of getting the update panel?).
Can anyone see what I might be doing wrong in the above?
Thanks :)
Well, to answer the query above - it does appear as if the placeholder somehow messes up the ScriptManager.RegisterStartupScript.
When I pull the control out of the placeholder and code it directly onto the page the Register script works correctly (I am also using the control itself as a parameter).
ScriptManager.RegisterStartupScript(this, GetType(), Guid.NewGuid().ToString(), script, true);
Can anyone throw any light on why an injected control onto a PlaceHolder would prevent the ScriptManager from correctly registering the script? I am guessing this might have something to do with the lifecycle of dynamic controls, but would appreciate (for my own knowledge) if there is a correct process for the above.
I had an issue using this in a user control (in a page this worked fine); the Button1 is inside an updatepanel, and the scriptmanager is on the usercontrol.
protected void Button1_Click(object sender, EventArgs e)
{
string scriptstring = "alert('Welcome');";
ScriptManager.RegisterStartupScript(this, this.GetType(), "alertscript", scriptstring, true);
}
Now it seems you have to be careful with the first two arguments, they need to reference your page, not your control
ScriptManager.RegisterStartupScript(this.Page, this.Page.GetType(), "alertscript", scriptstring, true);
I think you should indeed be using the Control overload of the RegisterStartupScript.
I've tried the following code in a server control:
[ToolboxData("<{0}:AlertControl runat=server></{0}:AlertControl>")]
public class AlertControl : Control{
protected override void OnInit(EventArgs e){
base.OnInit(e);
string script = "alert(\"Hello!\");";
ScriptManager.RegisterStartupScript(this, GetType(),
"ServerControlScript", script, true);
}
}
Then in my page I have:
protected override void OnInit(EventArgs e){
base.OnInit(e);
Placeholder1.Controls.Add(new AlertControl());
}
Where Placeholder1 is a placeholder in an update panel. The placeholder has a couple of other controls on in it, including buttons.
This behaved exactly as you would expect, I got an alert saying "Hello" every time I loaded the page or caused the update panel to update.
The other thing you could look at is to hook into some of the page lifecycle events that are fired during an update panel request:
Sys.WebForms.PageRequestManager.getInstance()
.add_endRequest(EndRequestHandler);
The PageRequestManager endRequestHandler event fires every time an update panel completes its update - this would allow you to call a method to set up your control.
My only other questions are:
What is your script actually doing?
Presumably you can see the script in the HTML at the bottom of the page (just before the closing </form> tag)?
Have you tried putting a few "alert("Here");" calls in your startup script to see if it's being called correctly?
Have you tried Firefox and Firebug - is that reporting any script errors?
When you call ScriptManager.RegisterStartupScript, the "Control" parameter must be a control that is within an UpdatePanel that will be updated. You need to change it to:
ScriptManager.RegisterStartupScript(this, this.GetType(), Guid.NewGuid().ToString(), script, true);
The solution is to put the scripts in an outside js file (lets called 'yourDynamic.js') and re-register de file everytime you refresh the updatepanel.
I use this in the updatepanel_prerender event:
ScriptManager.RegisterClientScriptBlock(UpdatePanel1, UpdatePanel1.GetType(), "UpdatePanel1_PreRender", _
"<script type='text/javascript' id='UpdatePanel1_PreRender'>" & _
"include('yourDynamic.js');" & _
"removeDuplicatedScript('UpdatePanel1_PreRender');</script>" _
, False)
In the page or in some other include you will need this javascript:
// Include a javascript file inside another one.
function include(filename)
{
var head = document.getElementsByTagName('head')[0];
var scripts = document.getElementsByTagName('script');
for(var x=0;x<scripts.length;> {
if (scripts[x].getAttribute('src'))
{
if(scripts[x].getAttribute('src').indexOf(filename) != -1)
{
head.removeChild(scripts[x]);
break;
}
}
}
script = document.createElement('script');
script.src = filename;
script.type = 'text/javascript';
head.appendChild(script)
}
// Removes duplicated scripts.
function removeDuplicatedScript(id)
{
var count = 0;
var head = document.getElementsByTagName('head')[0];
var scripts = document.getElementsByTagName('script');
var firstScript;
for(var x=0;x<scripts.length;> {
if (scripts[x].getAttribute('id'))
{
if(scripts[x].getAttribute('id').indexOf(id) != -1)
{
if (count == 0)
{
firstScript = scripts[x];
count++;
}
else
{
head.removeChild(firstScript);
firstScript = scripts[x];
count = 1;
}
}
}
}
clearAjaxNetJunk();
}
// Evoids the update panel auto generated scripts to grow to inifity. X-(
function clearAjaxNetJunk()
{
var knowJunk = 'Sys.Application.add_init(function() {';
var count = 0;
var head = document.getElementsByTagName('head')[0];
var scripts = document.getElementsByTagName('script');
var firstScript;
for(var x=0;x<scripts.length;> {
if (scripts[x].textContent)
{
if(scripts[x].textContent.indexOf(knowJunk) != -1)
{
if (count == 0)
{
firstScript = scripts[x];
count++;
}
else
{
head.removeChild(firstScript);
firstScript = scripts[x];
count = 1;
}
}
}
}
}
Pretty cool, ah...jejeje
This part of what i posted some time ago here.
Hope this help... :)
I had an issue with Page.ClientScript.RegisterStartUpScript - I wasn't using an update panel, but the control was cached. This meant that I had to insert the script into a Literal (or could use a PlaceHolder) so when rendered from the cache the script is included.
A similar solution might work for you.
DO NOT Use GUID For Key
ScriptManager.RegisterClientScriptBlock(this.Page, typeof(UpdatePanel)
Guid.NewGuid().ToString(), myScript, true);
and if you want to do that , call Something Like this function
public static string GetGuidClear(string x)
{
return x.Replace("-", "").Replace("0", "").Replace("1", "")
.Replace("2", "").Replace("3", "").Replace("4", "")
.Replace("5", "").Replace("6", "").Replace("7", "")
.Replace("8", "").Replace("9", "");
}
What worked for me, is registering it on the Page while specifying the type as that of the UpdatePanel, like so:
ScriptManager.RegisterClientScriptBlock(this.Page, typeof(UpdatePanel) Guid.NewGuid().ToString(), myScript, true);
Sometimes it doesnt fire when the script has some syntax error, make sure the script and javascript syntax is correct.
ScriptManager.RegisterStartupScript(this, this.GetType(), Guid.NewGuid().ToString(),script, true );
The "true" param value at the end of the ScriptManager.RegisterStartupScript will add a JavaScript tag inside your page:
<script language='javascript' defer='defer'>your script</script >
If the value will be "false" it will inject only the script witout the --script-- tag.
I try many things and finally found that the last parameter must be false and you must add <SCRIPT> tag to the java script :
string script = "< SCRIPT >alert('hello!');< /SCRIPT>";
ScriptManager.RegisterClientScriptBlock(Page, Page.GetType(), key, script, **false**);
I am validating a zip code using Javascript that is generated server-side, and injected when a LinkButton is clicked. Then, I retrieve the return value by calling a server-side function when the page loads.
This works nicely, but the problem is that the ViewState is completely lost after PostBack. Below is the code, starting with the page_load event, the button click event, and then the callback called from the page_load event.
Is there a way I can somehow save the ViewState, maybe easily in a session variable? Or is there a workaround I can use?
// In Page_Load
if (Request.Form["__EVENTTARGET"] == "CallFunction") {
GetValidateZipCodeScriptReturnValue(Boolean.Parse(Request.Form["__EVENTARGUMENT"].ToString()));
}
// OnClick for LinkButton
private bool ValidateZipCode(string zip) {
StringBuilder script = new StringBuilder();
script.Append("<script language='javascript' type='text/javascript'>");
script.Append(#"var regex = /^\d{5}$|^\d{5}-\d{4}$/;");
script.Append("__doPostBack('CallFunction', regex.test(" + zip + "));");
script.Append("</script>");
Type t = GetType();
if (!ClientScript.IsClientScriptBlockRegistered(t, "ValidateZipCodeScript")) {
ClientScript.RegisterClientScriptBlock(t, "ValidateZipCodeScript", script.ToString());
}
return false;
}
// Method called on PostBack to get the return value of the javascript
private void GetValidateZipCodeScriptReturnValue(bool valid) {
m_ZipCode = uxZip.Text;
if (valid) {
Response.Redirect(string.Format("~/checkout/overview.aspx?pc={0}&zc={1}",
ProductCode, ZipCode));
}
else {
Alert.Show("The entered zip code is invalid. Please ensure the zip code is a valid zip code.");
SetupPostBackViewState();
ScrollToZipCode();
}
}
Why not just use the OnClick event of the LinkButton? Or, better yet, look into the CustomValidator control, since it looks like all you're trying to do is validate a zip code and that's exactly what a CustomValidator can do (you'll need to look at the ClientValidationFunction, which is where you want to put your regex test).