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Question

Why is the label not changing color using RegisterClientScriptBlock?

Answer 1

A:

Change this line:

var lbl = document.getElementById('lblDisplayDate');

to:

var lbl = document.getElementById('<%= lblDisplayDate.ClientID %>');

Also, this probably isn't doing what you want it to do anyway. Try adding:

OnClientClick="changecolor()"

to your <asp:Button /> tag.

Edit At this point I am pretty confused as to what exactly you are trying to accomplish...

If you just want to change the color of the label without posting back, change your <asp:Button /> to a normal <input type="button" /> with an onclick handler and call your script, like this:

<input type="button" ... onclick="changeColor();" />

If you want to change the color of the label while posting back, then just change the label's background in the code-behind like this:

protected void btnPostBack2_Click(object sender, EventArgs e)
{
    /* ... other stuff goes here ... */
    lblDisplayDate.BackColor = Color.Red;
    /* ... other stuff goes here ... */
}

Sean Bright 2009-03-20 16:29:37

I changed it, but it is not changing the color still.

Xaisoft 2009-03-20 16:31:48

See my edit above.

Sean Bright 2009-03-20 16:34:02

I added the OnClientClick and it changes the color, but then the page reloads right after that and it goes back to being black.

Xaisoft 2009-03-20 16:37:23

Is there a way to persit the color or is it better to just use RegisterStartUpScript if doing things in Page_Load

Xaisoft 2009-03-20 16:38:10

I am expirementing with RegisterStartupScript and RegisterClientScriptBlock. If I use RegisterStartupScript, the page posts back and the color changes, but it did not with RegisterClientScriptBlock, but I was told that if I use it in a function it would work, so I am trying that out.

Xaisoft 2009-03-20 17:11:49

If you want to stop the post back occuring then at the end of your changecolor() function add return false;

OneSHOT 2009-06-15 21:32:30

Answer 2

A:

like what Sean already stated: it is best to use OnClientClick in this case. OnClientClick would prevent a postback occuring - it is done dynamically using javascript. All u need to do is preference it to the javascript function.

I do not understand y u want to do a "RegisterStartupScript and RegisterClientScriptBlock" on colour change. These should be used when u want to add javascript from the code behind, but seeing that u have it written out already in the aspx page, its use is pointless.

waqasahmed 2009-06-15 21:27:27

Answer 3

A:

Check this out. I have modified your code and its working fine now without postback.

<html xmlns="http://www.w3.org/1999/xhtml"&gt;  
<head runat="server">  
    <title>Untitled Page</title>
    <script type="text/javascript" language='javascript'>
       function changecolor() {
           var lbl = document.getElementById('lblDisplayDate');
           lbl.style.color = 'red';
       };
</script>
</head>
<body>
    <form id="form1" runat="server">
<div>
<asp:Label ID="lblDisplayDate" runat="server" 
           Text="Label"></asp:Label><br />

<asp:Button ID="btnPostBack2" runat="server" 
            Text="Register Client Block Script" 
            OnClientClick="changecolor(); return false" />

    </div>
    </form>
  </body>
</html>

hope this helps

A Bright Worker 2010-04-20 05:40:49

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Why is the label not changing color using RegisterClientScriptBlock?

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