I'm trying to write a bookmarklet that tracks a package in the mail. First it checks to see if the tracking page is open, if not it opens it in a new tab, and then sets the value of the form to the tracking number. Finally, it submits the form. What I'm so far unable to do is set the value of the form in the case where the bookmarklet opens up a new tab.

Here's what I have:

javascript: (function(){
var trackingNumber = "/*tracking number*/";
var a = document.forms.trackingForm;
if ('http://fedex.com/Tracking' == document.location) {
trackingForm.trackNbrs.value = trackingNumber;
document.forms.trackingForm.submit();
}
else {
window.open('http://fedex.com/Tracking');
this.window.onload = function(){ //This seems to be the problem
trackingForm.trackNbrs.value = trackingNumber;
onload(document.forms.trackingForm.submit());
}
}
})();

Any ideas?