document.formname.submit is not a function Error in javascript

In my case i have 2 radio buttons

<input type="radio" name="test" value="1"  OnClick="javascript:document.formname.submit()"/>
<input type="radio" name="affiliates" value="2"   OnClick="javascript:document.affiliatesform.submit()" /> 

But in the same form as my my requirement i put one sumit button like

<input type="submit" name="submit" value="GO">
 
This means i have have a function trying to call the form's submit() method, but you also have a button which is called submit(). This causes a conflict in javascript, because the submit method is already bound to that button.

i just resolve this problem with change the name of the submit button

<input type="submit" name="print" value="GO">

login is very simple enjoy :)