javascript - Access a variable of iframe from parent

Question

script of iframe

<script type="text/javascript" >
var a=5;
</script>

script of parent window

<script type="text/javascript" >
function close()
{
var check=document.getElementById("iframeid").contentDocument.a;
alert(check)
}
</script>

I want to access the variable which is defined inside the iframe from parent. But the above code doesn't work properly can anyone give an idea to implement this.

Answer 1

Using contentWindow instead of contentDocument works for me:

var check = document.getElementById("iframeid").contentWindow.a;

Also, ensure that the domains match and that you are using a webserver to test (I got a protocol warning when testing from the file system).