Función javascript con arreglo de checkbox

[_cronos2]

Código Javascript:

function habil(obj){
 document.getElementById(obj.id.replace('chk','select')).disabled=!obj.checked;
}
 

Código HTML:

<input type="checkbox" id="chk1" name="chk1" onchange="habil(this);" value="1" />
<select id="select1" name="select1" disabled>
<option value="value1">option 1</option>
<option value="value2">option 2</option>
<option value="value3">option 4</option>
</select>
 

Saludos (: