How can I ignore window.onpopstate on page load?

To react on popstate event, you need to push some state onto the session history.

For example add this line to the document ready section:

history.pushState(null, null, window.location.pathname);

Not ideal, but it works in Chrome, Firefox and other browsers as well.

Then the event is fired correctly when user clicks on Back or Forward button, also when history.back(), history.forward(), history.go() methods are called manually. Each time when popstate has been invoked, you have to push another state again to make it working.

See also:

• Single-Page Apps and HTML5 pushState
• How to Detect Browser Back Button event - Cross Browser

Check for boolean truth of event.state in popstate event handler:

window.addEventListener('popstate', function(event) {
    if (event.state) {
        alert('!');
    }
}, false);

To ensure this will work, always specify a non-null state argument when calling history.pushState() or history.replaceState(). Also, consider using a wrapper library like History.js that provides consistent behavior across browsers.

I had a similar problem and i had to validate to make sure if page was loaded completely.

I used something like this :

var page_loaded = false;    
window.onpopstate = function(event){
    if(!page_loaded){
       page_loaded = true;
       return false;
     }
    //Continue With Your Code
}