Passing the parent form on the onclick event to javascript function

Your script doesn't know what form is. You need to specify document.forms[0].ip.value instead.

If there are more than one form on the document then it will be better if you store the form element in variable first. You can have an id on the form for that...

<form id="formID">

and in submit_value function you can have

var myForm = document.getElementById('formID'); alert(myForm.ip.value);

Edit:

You can use this.form for onClick of anchor tag.