window.opener is not working in Firefox

Question

I am accessing variable from parent to child window using window.opener. It works in IE and Chrome but not works in Firefox. Below is line of code that we use:

// to set the value in parent page
window.opener.varA = "TEST#1234";


//get the value in child page

varA =  window.opener.varA;

But it return varA as undefined in Firefox and return the varA= "TEST#1234" in Google Chrome and IE. Can anyone help me on this how can I get the value of varA?