I need to call a javascript function from C# code. I am getting object expected error

[vamshi2804]

//javascript function
<script language="javascript" type="text/javascript">  
       function popModal() {   
           $find('ModalPopupExtender').show();            
       }    
  
</script>  

//C# code

protected void Page_Load(object sender, EventArgs e)
{
   if (!Page.IsPostBack)
   {
      string script = "<SCRIPT LANGUAGE='JavaScript'> ";
      script += "popModal();";
      script += "</SCRIPT>";
  this.RegisterClientScriptBlock("ClientScript", script);
     }
 }

[Frinavale]

Well you're getting that message because JavaScript couldn't not find an element with the ID "ModalPopupExte nder". You need to provide the ID of the the ModalPopupExten der to the method. You can do this using the ClientID of the ModalPopupExten der.

Like this:

protected void Page_Load(object sender, EventArgs e)
{
   if (!Page.IsPostBack)
   {
      string script = "<SCRIPT LANGUAGE='JavaScript'> ";
      script += "popModal(" + ModalPopupExtender1.ClientID + ");";
      script += "</SCRIPT>";
  this.RegisterClientScriptBlock("ClientScript", script);
     }
 }

You'll have to change your JavaScript to accept the ID of the ModalPopupExten der as a parameter...and use that with the $find method:

//javascript function
<script language="javascript" type="text/javascript">  
       function popModal(ModalPopupExtenderClientID) {   
           $find(ModalPopupExtenderClientID).show();            
       }    
 
</script>

[vamshi2804]

Well you're getting that message because JavaScript couldn't not find an element with the ID "ModalPopupExte nder". You need to provide the ID of the the ModalPopupExten der to the method. You can do this using the ClientID of the ModalPopupExten der.

Like this:

protected void Page_Load(object sender, EventArgs e)
{
   if (!Page.IsPostBack)
   {
      string script = "<SCRIPT LANGUAGE='JavaScript'> ";
      script += "popModal(" + ModalPopupExtender1.ClientID + ");";
      script += "</SCRIPT>";
  this.RegisterClientScriptBlock("ClientScript", script);
     }
 }

You'll have to change your JavaScript to accept the ID of the ModalPopupExten der as a parameter...and use that with the $find method:

//javascript function
<script language="javascript" type="text/javascript">  
       function popModal(ModalPopupExtenderClientID) {   
           $find(ModalPopupExtenderClientID).show();            
       }    
 
</script>

Thank you for your quick response.

But I still get the same error.

I tried like below also

script += "popModal(' " + ModalPopupExten der1.ClientID + "');";

[Frinavale]

What exactly are you trying to do?
The ModalPopupExten der has it's own JavaScript aspect that it uses to display itself. You shouldn't be trying to find it on the page...you should be calling it's methods to display it.

-Frinny