<INPUT TYPE="checkbox" onclick="t.disabled=!this.checked?true:false">
<INPUT TYPE="text" NAME="" id="t" disabled>
<INPUT TYPE="text" NAME="" id="t" disabled>
<input type="checkbox" onpropertychange="test.disabled=!this.checked">
<input type="text" name="test" disabled>
<input type="text" name="test" disabled>