here is a sample script showing ho to pupulate a text box with the valu of the selected item and another with the lable of the selected itemL
<form id="form1" name="form1" method="post" action="">
<select name="selectList" id="selectList" onChange="document.form1.txtLable.value = document.form1.selectList[document.form1.selectList.selectedIndex].text; document.form1.txtValue.value = document.form1.selectList[document.form1.selectList.selectedIndex].value">
<option value="">Please make a selection</option>
<option value="1">one</option>
<option value="2">two</option>
<option value="3">three</option>
<option value="4">four</option>
<option value="5">five</option>
</select>
Lable
<input type="text" name="txtLable" id="txtLable" />
Value
<input type="text" name="txtValue" id="txtValue" />
</form>