Extension Help

I don't normally use javascript, but I'm writing a script for greasemonkey to extend a specific page on stumbleupon.com.
Basically, I've just started, and I'm trying to add a textbox to the page.

Code:

---

// ==UserScript==
// @author        Francis Stokes
// @name          Recent Shares Ext.
// @namespace      rse
// @description    Extension to the stanndard Recent Shares Page
// @include        http://*.stumbleupon.com/shares/
// ==/UserScript==

var tb = document.createElement('input');
tb.setAttribute("type", "text");
var f = document.forms[0];
f.appendChild(tb);

---

No textbox in sight. I don't think Im doing it right.
Any corrections would be helpful.

Hi there francisstokes,

the probable reason for it not working is that you have not allowed the page to load before calling the script.
This means that document.forms[0] does not as yet exist.

Also, for the page to validate you need your form to to be coded either like this...

Code:

---


<form action="#">
<div id="myform">

</div>
</form>


---

...or this...

Code:

---


<form action="#">
<fieldset>
<legend></legend>

</fieldset>
</form>


---

For the first option use this script...

Code:

---


<script type="text/javascript">
if(window.addEventListener){
  window.addEventListener('load',mytest,false);
 }
else {
if(window.attachEvent){
  window.attachEvent('onload',mytest);
  }
 }

function mytest(){
// ==UserScript==
// @author        Francis Stokes
// @name          Recent Shares Ext.
// @namespace      rse
// @description    Extension to the stanndard Recent Shares Page
// @include        http://*.stumbleupon.com/shares/
// ==/UserScript==

  tb=document.createElement('input');
  tb.setAttribute('type','text');
  f=document.getElementById('myform');
  f.appendChild(tb);
 }
</script>


---

...and the second use this...

Code:

---


<script type="text/javascript">
if(window.addEventListener){
  window.addEventListener('load',mytest,false);
 }
else {
if(window.attachEvent){
  window.attachEvent('onload',mytest);
  }
 }

function mytest(){
// ==UserScript==
// @author        Francis Stokes
// @name          Recent Shares Ext.
// @namespace      rse
// @description    Extension to the stanndard Recent Shares Page
// @include        http://*.stumbleupon.com/shares/
// ==/UserScript==

  tb=document.createElement('input');
  tb.setAttribute('type','text');
  f=document.forms[0][0];
  f.appendChild(tb);
 }
</script>


---