When you assign something an ID in asp.net such as:
<asp:Label runat="server" ID="mylabel" Text="some text"></asp:Label>
The code behind ID you use to reference that object is mylabel.
However after the site has compiled and is running the ID in the HTML changes to something a bit more abscure
<asp:Label runat="server" ID="ct100_blahblah_what_mylabel" Text="some text"></asp:Label>
And I cannot (don't know how) to reliably predict what it will be to select it with javascript.
Is there a way to ask the server what the ID for that label is at any given moment?
What are some keywords could use to find out more about this phenomenon?
You need the ClientID property. This contains the generated id of the control at runtime. You could emit some JavaScript in the code behind that sets the client id of your control to a JavaScript variable so you can reference it.
EDIT: added example
The following will find the label using the ClientID and then update its text.
<html>
<body>
<asp:Label runat="server" ID="mylabel" Text="some text"></asp:Label>
<script language="javascript">
var mylabelID = "<%= mylabel.ClientID %>";
var label = document.getElementById(mylabelID);
label.innerHTML += " changed";
</script>
</body>
</html>
I believe you are looking for the ClientID property.
The ClientID value is often used to
programmatically access the HTML
element rendered for a control in
client-side script.
Your other option is to wrap your control in an HTML element like this:
<span id="foo">
<asp:Label runat="server" ID="mylabel" Text="some text"></asp:Label>
</span>
Since this outer element does not have the runat="server" attribute, its id will not be changed on render. This would mean that your JavaScript function would have to to be changed to pull an inner element from the span foo or if you are using a JavaScript framework like jQuery you could pull the label back like this:
$("span#foo span");
Related
I have following html in my aspx page
<asp:Textbox id="myTextField" runat="server" cssclass="mycssclass" data-control-id="<%= search.ClientID %>"></asp:textbox>
<asp:Button ID="search" runat="server" Text="Search" />
the problem is "<%= search.ClientID %>" render as it is in the aspx file. i need to render the client id of control.
Thy this :
And call
this.DataBind(); in page_Load
(notice change in <%#)
<asp:Textbox id="myTextField" runat="server" cssclass="mycssclass" data-control-id="<%# search.ClientID %>"></asp:textbox>
Another (more convenient solution) is to use html elements which are not server side :
<input type='text' id="myTextField" runat="server" class="mycssclass" data-control-id="<%= search.ClientID %>" />
and then get it via Request.Form[...] ( via name attribute)
If you want to know what the client ID will be, then search and read about the setting "ClientIDMode" - setting it to Static, for example, will set the client-side ID in the DOM equal to the server side ID that you set. Just make sure have only one instance of that Control on your page otherwise you have more than one control with that ID, and that won't fly. If that control will be in a repeater, item template or any other "repeating" control, then add an index counter for the loop to dynamically alter then ID slightly.
im looking to select the follow element by id toggleThisDiv. The markup looks like:
<li id="liCategory" runat="server">
<asp:HyperLink ID="lnkCategory" runat="server">
<span><asp:Literal ID="litCategory" runat="server" Visible="true" /></span>
<asp:Image ID="imgMan" runat="server" Visible="false" /></asp:HyperLink>
<asp:Button ID="btnToggleDiv" runat="server" Text="+" Visible="false" />
</li>
<div id="toggleThisDiv" runat="server" style="display:none;margin-top:-16px;">
And the jQuery:
$(document).ready(function () {
$('[id*="btnToggleDiv"]').click(function () {
$(this).next().slideToggle(100);
return false;
});
});
This works when the button is outside of the listitem but this is all inside a repeater and if i leave it like that, all of the buttons created will be next to each other instead of within their associated list item.
I'm looking for something within jQuery that would allow me to select the next div (toggleThisDiv), is this possible?
Thankyou
Use unique ID's, or classes if generating elements where the same identifier will be used.
To target an element outside the current parent of the clicked element you can find the closest parent that matches a selector, and then the next element etc.
$(document).ready(function () {
$('[class*="btnToggleDiv"]').on('click', function () {
$(this).closest('li').next('div').slideToggle(100);
return false;
});
});
Use something like this to select the toggleThisDiv
$('#<%= toggleThisDiv.ClientID %>')
When the website is generated from your asp code, your IDs will be different than what you have given them. This is because they are run at server. Anytime that you are using runat server, use the format above to find the generated ID.
You should use a class inside to repeater though.
This code doesn't display the value, I don't know why?
I have server control:
<asp:TextBox ID="txtTest" runat="server" Visible="false" TextMode="MultiLine"
Rows="3" Columns="23" CssClass="white-scroll" />
in javascript function:
var eventText = document.getElementById('<%=txtTest.ClientID%>').value;
alert (eventText);
I enter text then click on button that call the javascript function, but the alert box doesn't display the entered text.
EDIT: when I initialize the text with Text="some text", it is displayed in alert, I want to enter text in client side and get the value of it in the Javascript function.
Thanks
Using label or textbox visible set false so it can access the value in JavaScript
Sol
1)
Make a div and set style="display:none;" so label is not display at UI(browser) but value can access in JavaScript.
This is because you server Control is called "txtTest" not "txtEventDescription"
change your javascript function to :
var eventText = document.getElementById('<%=txtTest.ClientID%>').value;
alert (eventText);
EDIT: ok, I see you've now changed the post to show the code and renamed the js control, so above is no longer relevant (for those who are confused by my answer) :-)
The problem is the Visible="false" - this control will not render into the client and will therefore not be accessible via javascript (as the HTML element does not exist client side)
So, hide the element using CSS and then call alert on it. Sample snippet
CSS
.hide-element {
display: none;
}
HTML Markup
<asp:TextBox ID="txtTest" runat="server"
Columns="23"
CssClass="white-scroll hide-element"
Rows="3"
TextMode="MultiLine"/>
JavaScript
var eventText = document.getElementById('<%=txtTest.ClientID%>').value;
alert (eventText);
This way you will definitely get an alert.
You alert is empty because you have not set the property Text for your asp:Textbox
Make it Visible="true" to your textbox and than test.
<asp:TextBox ID="txtTest" runat="server" TextMode="MultiLine"
Rows="3" Columns="23" CssClass="white-scroll" />
if "txtTest" textbox has visible="false" in that case its not render on html code on client machine and if it hasn't on client's html code then how javascript calls this textbox. Because when javascript search this textbox by its id it doesn't find and it gives an error.
you can assign any other custom attribute to the control i.e.
<asp:TextBox ID="txtTest" runat="server" Visible="false" TextMode="MultiLine"
Rows="3" Columns="23" CssClass="white-scroll"
clientID="myClientID" />
and then access control using jquery like
var txtVal = $('textbox[clientID=myClientID]').val();
hope it helps.
Hopefully this one is not too hard to understand but I just want the label values to be inputs into a javascript function. Might be better to explain with code:
ASP.NET Label code:
<asp:Label ID="LabelCL" runat="server" Text="A single int filled in by DB"></asp:Label>
Page Source:
<span id="ctl00_cpMainContent_LabelCL">7</span>
What I would like to achieve but am not sure how to do:
<span id="ctl00_cpMainContent_LabelCL"> <script type="text/javascript">functionX(7)</script> </span>
So basically just wrap the output int in the following:
<script type="text/javascript">functionX( VALUE FROM LABEL TEXT)</script>
within the
<span></span>
Try this
<asp:Label ID="LabelCL" runat="server" />
<script type="text/javascript">
var value = document.getElementById("<%= LabelCL.ClientID %>").innerHTML;
functionX(value);
</script>
If it is called just after render you can simply use LabelCL.Text, if you need the value after and if it can be edited you can do as the exemple above.
With jQuery you can use
$("[id$=LabelCL]")
to retrieve the element.
var span = document.getElementById('ctl00_cpMainContent_LabelCL'),
text = span.firstChild;
functionX(text.textContent);
Working Demo
or if defined in the Page use script tags to render out the client id for the span using
<%= LabelCL.ClientID %>
Try this:
<asp:Label ID="LabelCL" runat="server" Text="A single int"></asp:Label>
<button onclick="displayContent(<%= LabelCL.ClientID %>)">click me</button>
<script>
function displayContent(obj) {
alert(obj.innerText);
}
</script>
You almost had it:
<asp:Label runat="server" Text="<script type='text/javascript'>document.write(functionX(7));</script>"/>
Use this piece of code
onclick="myFunction(labelName.innerText)"
I'm trying to select an element from my webpage...
I have inserted a control into my page and i need to set some values an element inside the control at pageload from c# code.. The thing is, as soon as I insert the control into the page... A prefix is appended to the id name... Because of that new name, my css definition won't be appended...
Is there any way to access this element from C# without the need to make it an Id?
Edit: To clarify what Im trying to do here. Im trying to make a generic control, which gets a width and height set to it's parameters. I need to set this manually to the element by adding a style attribute. I can't make the element an id, because this will stop the possibility of making it generic.
This is whats inside of the control... the fact is, I need the imageRotatorDiv to be a class instead of an id. Otherwise i can't use multiple image rotators on one page.
But how can I select a class in a page from c# code? Is it possible?
<div id="imageRotatorDiv" runat="server">
<div class="imageRotator">
<asp:Repeater ID="rprImages" runat="server">
<ItemTemplate>
<asp:Image ID="imgItem" runat="server" />
</ItemTemplate>
</asp:Repeater>
</div>
</div>
you can define your style to a class name instead of id.
<asp:TextBox ID="MyText" CssClass="someclass" runat="server" />
html output
<input type="text" id="Something_MyText" class="someclass" />
css
.someclass { border:solid 1px red; }
In JQuery :
$("div[id$=MyDiv]").addClass("myDiv")
And you just need to define the myDiv CSS class. Or, to modify directly the style :
$("div[id$=MyDiv]").css("font-size", "14px");
JQuery details