CODEWITHSUNDEEP
c#javascriptasp.net
Ris
Ris

Reputation: 1164

Calling an ASP generated button click from a javascript

I've following button on my web control,

<asp:Button runat="server" ID="btnSave" Text="Save" onclick="btnSave_Click"  OnClientClick="myShowWaitScreenWithNoClose('Processing...', 'Saving survey.Please wait it may take minutes..');" CssClass="buttons" Height="46px" Width="212px" Visible="false"  />

and I'm trying to click this button using JavaScript from code behind. Like,

protected void Page_Load(object sender, EventArgs e)
{

 if (!IsPostBack)
   {
        ScriptManager.RegisterStartupScript(this, this.GetType(), "scr", "setTimeout(function(){document.getElementById('btnSave').click(); return false;}, 180000);", true);
   }
}

But it throws an error Error: TypeError: document.getElementById(...) is null

Upvotes: 0

Views: 188

Answers (3)

Icarus
Icarus

Reputation: 63956

Is returning null most likely because the id of the btnSave control is changed when it's rendered on the client side unless you use CliendIDMode="static"

For your code to work, you need to change it to:

  if (!IsPostBack)
   {
        ScriptManager.RegisterStartupScript(this, this.GetType(), "scr", "setTimeout(function(){document.getElementById('"+btnSave.ClientID+"').click(); return false;}, 180000);", true);
   }

Upvotes: 1

Muhammad Hani
Muhammad Hani

Reputation: 8664

To get a server-side control via Javascript, use the below

document.getElementById('<%=btnSave.ClientID%>').click();

Upvotes: 1

Brad M
Brad M

Reputation: 7898

It throws this error because the ID you declare is not the same as what is rendered. 

<asp:Button runat="server" ID="btnSave" clientIdMode="static">

Add the clientIdMode="static" attribute so your ID will render exactly as your declared it.

Upvotes: 3

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