JavaScript getElementById(...) is null or not an object IE

javascript internet-explorer getelementbyid

14,449

Solution 1

you do

document.getElementById('documentFrame2').onload = resizeIframe;

before the document is ready so the iframe can be found. call this in the onload- or document-ready-function or in a seperate javascript-block after the iframe.

Solution 2

Try wrapping

document.getElementById('documentFrame2').onload = resizeIframe;

Within:

window.onload = function(){

    document.getElementById('documentFrame2').onload = resizeIframe;
    window.onresize = resizeIframe;
    resizeIframe();
};

The iframe doesn't exist in the DOM until the page/Dom has loaded.

UPDATE:

Didn't see part of the code you posted.

You could keep onload = "resizeIframe" within the element itself and have the JavaScript in the head as:

function resizeIframe() {
    var height = document.documentElement.clientHeight;
    height -= document.getElementById('documentFrame2').offsetTop;
    height -= 20;
    document.getElementById('documentFrame2').style.height = height +"px";
 }


 window.onresize = resizeIframe;

That way you wouldn't need any JavaScript running after the element.

Solution 3

alert(document.getElementById('abcId').value);

alert(document.formName.elements['abcName'].value);

I expirienced the same issue i tried the 2nd one it worked.

14,449

Ali

Updated on June 04, 2022

Comments

Ali almost 2 years

This must be something very simple for the JavaScript experts out there. In the following code, I am trying to open an iframe to the full height of browser window.

    <%@ Page Language="C#" AutoEventWireup="true"  CodeFile="Default.aspx.cs" Inherits="_Default" %>

<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">

<html xmlns="http://www.w3.org/1999/xhtml">
<head runat="server">
    <title>Untitled Page</title>
         <script language="javascript" type="text/javascript">
    function resizeIframe() {
    var height = document.documentElement.clientHeight;
    height -= document.getElementById('documentFrame2').offsetTop;
    height -= 20;
    document.getElementById('documentFrame2').style.height = height +"px";
 };
document.getElementById('documentFrame2').onload = resizeIframe;
window.onresize = resizeIframe;
    </script>
</head>
<body>
    <form id="form1" runat="server">
    <div>
     <iframe src="standard-tube-map.pdf" id="documentFrame2" width="100%" onload="resizeIframe();" ></iframe> 
    </div>
    </form>
</body>
</html>

It works in Mozilla but in IE (only tested in IE8) it gives the error: 'document.getElementById(...) is null or not an object'. Can anybody suggest what should I change to make it work cross browser?

Many thanks, Ali

Ali almost 14 years

Thanks Peter, but this is only working if you resize the window.
Ali almost 14 years

Thanks Tomgrohl. After trying this, there is no error in the status bar, but the size of iframe is the default.
Ali almost 14 years

Much appreciate your effort, but its still not working for me in IE. It only becomes full height when I resize the window. Is there any other workaround? Thanks again.
Admin almost 14 years

On page load you could get it to run resizeIframe(). That would solve it. I've edited my answer as it was easier so check that.
Ali almost 14 years

Just removed the script from <head> and placed it inside <body> after the <iframe> and it worked. Thanks a ton!