Change your HTML to this:
<td width="30%">Do you accept Terms of Service agreement?</td>
<td width="10px" style="min-width: 10px"></td>
<td width="70%">
<input type="checkbox" name="TOS" value="Accept" onClick="EnableSubmit(this)"> I agree to Terms of Service agreement.
</td>
Reason it’s not working: you’re not passing your function anything. Actually, because you’ve not used parentheses with the function name, you’ve not called the function at all. Passing it this
in the context of the onclick
HTML event attribute means you’re passing a reference to the element’s DOM object, giving you access to its checked
property.