help me on dis topic

hi,
i have a combo box & 2 text box on my form for example:

<form id="form1" name="form1" method="post" action="">

<select name="payment_mode" id="payment_mode">
<option value="cash">Cash</option>
<option value="cheque">Cheque</option>
<option value="credit card">Credit Card</option>
</select>
<input type="text" name="cheque no." id="cheque no." />
<input type="text" name="bank_name" id="bank_name" />

Now I want to hide those text box when the selected value from combo is cash.
It works with the submit button but i dnt want to use submit button.
How to i determine the selected value of list without submission of form.

 

I guess it is javascript question and not php.

 

<form id="form1" name="form1" method="post" action="">

<select name="payment_mode" id="payment_mode" onchange="hide_for_cash(this.value);">
<option value="cash">Cash</option>
<option value="cheque">Cheque</option>
<option value="credit card">Credit Card</option>
</select>
<div id="div_textbox">
<input type="text" name="cheque no." id="cheque no." />
<input type="text" name="bank_name" id="bank_name" />
</div>
<javascript>
function hide_for_cash(value){
if(value=='cash'){

docuement.getElementById('div_textbox').style.display="none";
}else{
docuement.getElementById('div_textbox').style.display="inline";
}



}
</javascript>