Check if window is already open window.open

Question

I have a html page. In the body of the page I am calling onload event which calls javascript function to open a pop up window. here is the code:

Answer 1

To open a window and keep a reference to it between page refresh.

var winref = window.open('', 'MyWindowName', '', true);
if(winref.location.href === 'about:blank'){
    winref.location.href = 'http://example.com';
}

or in function format

function openOnce(url, target){
    // open a blank "target" window
    // or get the reference to the existing "target" window
    var winref = window.open('', target, '', true);

    // if the "target" window was just opened, change its url
    if(winref.location.href === 'about:blank'){
        winref.location.href = url;
    }
    return winref;
}
openOnce('http://example.com', 'MyWindowName');