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Textbox Onclick = clear value , on exit from textbox set the default value?

I have this in the
<asp:TextBox ID="svv" OnClick="this.value=''" runat="server">Hello...</asp:TextBox>
OnClick="this.value=''" // On mouse click in textbox it will deleted the text.
How can I set something like
Unclick"this.defautlvalue"; // something like this.
So, when I click the control it will clear the value, if I exit from the control (for example, clicking another textbox) it will return the default value of the textbox.
Thanks

Specifically with C# .NET WebForms you have a few options.
You can go completely front-end with jquery by doing something like this:
$('selector').blur(function() {
// Make sure you do some validation so it doesn't clear everytime
$('selector').val('My Default Text');
});
Or, if you are using the AJAX Control Toolkit, you can simply use The textbox Watermark Control, which will do exactly what you are talking about just by setting a few properties.
You can also go straight javascript like #m.edmondson explain in his answer.

I think you're looking for onBlur:
<input type="text" id="fname" onblur="upperCase()">
This will call upperCase() when the user leaves the box.

You can attach to the client-side onblur event which is called when the focus of your control changes.

Also worth storing the default value in an attribute on the input so you can refer to it in blur event. Believe in ASP.NET web forms you've got to add that attribute in the code-behind though.

WebBrowser and javascript

I am working with a website that has javascript that does some changes on the page load. However, when I load the page and handle the DocumentCompleted event, this change isn't there. If I then continue paste the DocumentCompleted event, I can see the change happen. However I need this change to happen during DocumentCompleted so I can check some things.
Is there an other event I can subscribe to, or a way to cause the webBrowser to do all the javscript on page?
Edit: This is what I am talking about.
I loaded a sample page just to show you, and clicked the submit button with all fields empty to generate an the error.
Here is the result:
http://s8.postimage.org/zfv6stcar/sfsdfsdfds.jpg
Now if I take the HTML at that precise moment from that WebBrowser control, and render it somewhere else, those errors go away. The same thing happens when the server sends back those errors. If I handle the DocumentCompleted event and take the html, it isnt there. But after the event, it shows up in the control.
Hope you understand, it's hard to explain.

The problem seems to be that the DocumentCompleted event is being fired before the javascript. You should do some reading on how client side/server side things function.
One option is to make a separate method for the DocumentCompleted event and call it form the javascript after it has been completed. This would get the sequencing of these events working properly, but is not very ideal.
Alternatively, you could call the javascript code at the beginning of your DocumentCompleted event. The link below gives a pretty good explanation of how to go about that.
http://forums.asp.net/t/1117189.aspx/1
Personally, I would avoid using javascript and do the validation on the client side .NET, but I don't know enough about the website to really say.
EDIT:
This should be the script you are looking for. Alternatively here is a thread related to your issue. Sorry I don't have the exact code as I don't have a project to test this on.
http://msdn.microsoft.com/en-us/library/system.web.ui.clientscriptmanager.registerstartupscript.aspx
Calling JavaScript Function From CodeBehind
RE-EDIT:
What is happening on the link you provided in the comments, is that each textbox is calling some javascript as well as the submit button. The best way to examine this is using the "Inspect Element" in the right-click menu on Google Chrome. For example, doing this on the textbox would show that it is registered with a few events:
onfocus="$('f_tip_Username').style.display = 'inline'"
onblur="$('f_tip_Username').style.display = 'none'"
onchange="$('f_err_Username').style.display = 'none'"
The first the element with the ID 'f_tip_Username', sets the display style of that element to inline (visible).
The submit button calls the following:
onclick="return o_edit_profile_form.validate()"
Doing a find on "o_edit_profile_form" in the source code, you can find the exact javascript location that is being called. Enjoy!
FINAL EDIT (hopefully?):
Follow these steps: go to your site, right click and go view source. Do a find for "f_tip_Username". This is the ID of one of the div tags being used. The third entry of it, should be a "div tag" that is used under the first textbox to warn of "min 3 characters".
You'll notice above that in the code is a input type "text" with the Name "Username". Notice the three events it has registered in it:
onfocus="$('f_tip_Username').style.display = 'inline'"
onblur="$('f_tip_Username').style.display = 'none'"
onchange="$('f_err_Username').style.display = 'none'"
These either hide or make visible, the div tag we found (f_tip_username) and also a separate div tag (f_err_Username) which is the error message div tag. Let me know if you are not able to find these in the source. Follow the steps I provided and you will find it in the "view source" OR in the DocumentText.

.NET button in div with style="display:none" not firing

I have a pretty simple web-form set up in .Net where I am leveraging jQuery for some of the functionality. I am using the DOMWindow portion for part of the presentation layer.
There is a login form in a div that is set to display:none. When a user clicks a button on the page, it displays the login form. However the .Net button for the login form will not fire it's event when display is set to none. If i take this out, it fires fine. I have also tried using the visibility attribute, but no luck.
the div code is:
<div id="Login" style="display:none;">
The launching code is:
click here to login.<br />
the jQuery code is:
function LaunchLoginWindow() {
$(document).append("#Login");
$.openDOMWindow({
loader: 1,
loaderImagePath: 'animationProcessing.gif',
loaderHeight: 7,
loaderWidth: 8,
windowSourceID: '#Login'
});
}
Any help or explanation that anyone can offer is appreciated.
I noticed i had some code in there defining a client-side function on the Login div. I removed this so as to eliminate it as a possible issue.

I can see in your code that you are appending the div #Login but not setting its style property back to normal like block so. Set it back to block and i am sure it will work
try adding somthing like:
$(document).append("#Login").show();

OK, after playing around with this using firebug, I found the issue: When the jQuery plug-in DOMWindow creates its display layer, it appends to the HTML node of the DOM, which places the control outside the asp.net form tag. Therefore the button and actions associated with it via the DOMWindow are not recognized by .Net. So i edited the DOMWindow source file to append to the DOM form node rather then the html node.
The drawback is that the source has now been customized and will have to be QA'd thoroughly, especially if any further changes are made. But I hope to manage this effectively via commenting in the file.
Hope this helps anyone else who hits this issue.
pbr

Removing default text from text box

I got this Text box with default value as "First Name" ..Now when I click inside this text box to enter name , this value "First Name" keeps on displaying. What I want is to the text box to clear as soon as I click inside it. What property do I need to set in mt textbox tag ?
[Edit]
ok anything from Telerik that I can use to do that ?

There is not out of the box functionality in TextBox that will accomplish this, but the ASP.Net Ajax Toolkit has a Watermark Extender that will do everything you want.
I have used both, but now personally use a jQuery Watermark Plugin
Either will work just fine, choose based on your needs.
According to the Telerik docs you just have to set the EmptyMessage property on their TextBox control. Demo Page Here

In the code behind, on Page Load you can add the following code to achieve this
TextBox1.Attributes.Add("onClick", "javascript:if(this.value=='First Name'){this.value='';}");

You can use the method suggested by #Josh. If you do not want to use Ajax Toolkit controls or JQuery you could write it on your own using Javascript. Write a function which gets called when the foucs is received by the textbox control. I thik the function is called onfocus or just focus in Javascript.

Hi I just wrote this small function which will achieve your desired result
function clearInputBox(x,prefil){
if(x.value == prefil){
x.value = '';
}
}
Your input box looks like this
<input type='text' value='First Name' onfocus="clearInputBox(this,'First Name')" />

May be this will help you

Taking Shobans advice one step farther, you could add something like this to your Page subclass
protected override void OnInitComplete(EventArgs e)
{
string jsString = "javascript:if(this.value=='" + TextBox1.Text + "'){this.value='';}";
TextBox1.Attributes.Add("onFocus", jsString);
base.OnInitComplete(e);
}
What this will do is, it will always consider that default string is the one this controll contains at esign time (the initial one in your .aspx file), so you wont have to manually change it in codebehind every time you change your .aspx. Remember, that OnIinitComplete fires before any viewstate or postback data has been applied, but after the controlls on your page have been set to their default values.
P.S. As anishMarokey pointed, use onFocus vs onClick, since fields can gain focus without clicks via Tab key.

user control event handler lost on postback

I have a menu usercontrol called LeftMenu that has a bulletedlist of linkitems. It's on the ascx page as such:
<asp:BulletedList ID="PublisherList" DisplayMode="LinkButton" OnClick="PublisherList_Click" cssClass="Menu" runat="server"></asp:BulletedList>
I databind the list in the page_load under if(!isPostBack)
I'm having an issue on a page that loads the control. When the page first loads, the event handler fires. However, when the page posts back it no longer fires and in IE8, when I'm debugging, I get "Microsoft JScript runtime error: Object expected" in Visual Studio pointing at "__doPostBack('LeftMenu$PublisherList','0')." In FF I don't get the error, but nothing happens. I'm not loading the control dynamically, it's loaded on the aspx page using:
<%# Register TagPrefix="Standards" TagName="LeftMenu" Src="LeftMenu.ascx" %>
<Standards:LeftMenu ID="LeftMenu" runat="server"/>
Any ideas of where I'm losing the event handler?
I just realized this is happening on another user control I have as well. A text box and a button and I'm using the default button to make sure pressing the enter key uses that button. .Net converts that in the html to:
<div id="SearchBarInclude_SearchBar" onkeypress="javascript:return WebForm_FireDefaultButton(event, 'SearchBarInclude_QuickSearchButton')">
so as soon as i enter a key in the box I get a javascript error at the line saying "object expected." It seems like the two issues are related.
Edit Again: I think I need to clarify. It's not that I'm clicking on the menu item and it can't find the selected item on postback. I have this search page with the left navigation on it and then the main content of the page is something that causes a postback. Everything is fine with this postback. Once that page has been posted back, now if I click on the bulleted list in the left navigation I get a javascript error and it fails. The page_init for the LeftMenu control is never called.

It sounds like you might be losing the click because you are not DataBinding the list on PostBack. Therefore, the post back is trying to refer to a control (a specific bulleted list item) that does not exist.
You should try binding the list again on PostBack just to see if that fixes your issue. BUT, what should REALLY happen is that the LeftMenu and the BulletedList should store their information into ViewState so that you can ensure that the data that was shown to the user on their initial page load is the same data that the PostBack is processing and working with.

If you have EnableViewState=true for your UserControl and all controls within it, everything should work fine. With ViewState enabled, ASP will reinflate your controls from ViewState after Init has fired. This means that the postback event arg (which points to an index in your control list) will still find the control in that list position. Otherwise the list is empty on postback.
However, ViewState is the work of the devil and was designed simply to foster the illusion that you are working in a stateful environment. It is okay to use it for small amounts of data but typically not advisable for templated controls like repeaters and lists because you have no idea how much data is going to be created in ViewState.
If you are dealing with static, or relatively static data, store it in the application cache and rebind your lists in Page.Init every time (note that it has to be in Init because post-init is when ASP rebinds from ViewState; if you get in there first, your data will be used instead).
If you are dealing with volatile data, you have a problem because the data you rebind must be exactly the same as the original page request, otherwise the postback events will be firing against the wrong rows. In that case you need to either store your initial data in Session or you simply store the list of rows ids (in a hidden variable or Session) and you recreate the data to bind against from the ids each time.
An even better solution is to not use postback events at all. Try to turn all your events into GETs that have an ID on the query string. You can still create the list using binding the first time through the page (as you are currently doing), and you can even GET the same page with a new ID.
If you need to keep state on the same page but need to respond to the user changing a radio button selection (or something else), think about using Ajax calls to update the screen. You also do that with an ID that you pass to the Ajax call.
In general, the more you move from using stateful ASP, the lighter and more responsive your pages will become. You will also be in a better position to move to stateless MVC if necessary. You will also save lots of time lost to debugging obscure problems because ViewState is not available when you need it to be.
The best analysis of ViewState I've read is in the link below. If you fully understand how it works, you can continue to use it without necessarily incurring the costs.
http://weblogs.asp.net/infinitiesloop/archive/2006/08/03/truly-understanding-viewstate.aspx

It's possible that this might be javascript related, and that a script that is loading earlier in the page is throwing an error and causing the page to not be loaded properly.
Are your usercontrols loading any javascript onto the page? Can you check for javascript errors on the initial load of the page?

I moved the code into an existing project we have and for some strange reason, I stopped getting the javascript errors and instead got:
"Invalid postback or callback argument. Event validation is enabled using <pages enableEventValidation="true"/> in configuration or <%# Page EnableEventValidation="true" %> in a page.
For security purposes, this feature verifies that arguments to postback or callback events originate from the server control that originally rendered them. If the data is valid and expected, use the ClientScriptManager.RegisterForEventValidation method in order to register the postback or callback data for validation."
I haven't quite figured out where I'm supposed to put the register event validation with a user control, but in the mean time I just set enableeventvalidation=false and it seems to work now.

It looks like the doPostBack function is missing since its arguments are literals so they couldn't be the cause. Is that one of your own functions or did you mean to call the ASP __doPostBack function?
Have a look at the Firefox error console or allow script debugging in IE and see exactly what object can't be found. Even better, download Firebug and debug it.

I had a similar issue. It turned out that Akamai was modifying the user-agent string because an setting was being applied that was not needed.
This meant that some .NET controls did not render __doPostBack code properly. This issue has been blogged here.