Is a javascript exception being thrown?
First, document.forms[0] has burned me in the paste when the site template was modified to add a search form. Instead, you're passing "this" in the call, add a _this parameter in the function declarations and use _this.form in place of document.forms[0]. Once this is changed and if you're still having issue, start inserting alert('I'm here') and walk through your functions. Most likely you have an exception being thrown.