Getting JavaScript error 'remove_readyStateComplete' is not a function in dynamics 2015 IFrame when calling Xrm.Page.getControl('...').remove_readyStateComplete()

Hi 

I have added one IFrame in opportunity main page, I am calling following function on IFrame load -

function loadIFrame(context) {

Xrm.Page.getControl('...').remove_readyStateComplete();

}

at line Xrm.Page.getControl('...').remove_readyStateComplete() i am getting following error -

I am using Microsooft Dynamics 2015 online account.

This code was working in CRM 2013

Can anyone help me what is alternate method in crm 2015

Thanks in advance.