Using a bookmarklet to track a package

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 op开发者_如何转开发ens 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?

---

window.open opens a new window, so if this is going to work at all (I have little experience with bookmarklets), you would have to address the new window directly. Something like this:

else {
new_window = window.open('http://fedex.com/Tracking');
new_window.onload = function(){ 
new_window.document.trackingForm.trackNbrs.value = trackingNumber;
new_window.document.forms.trackingForm.submit(); 
// I didn't get at all what the onload() was for, re-add if necessary
}