How to prevent clicking on a checkbox's label span. clickable only on checkbox only

I have a checkbox in jsp form with label in it containing span which get displayed after inspecting element.i want checkbox to be clickable only when i click on checkbox only.if i click on checkbox label span it should not be clickable. i am not allowed to modify this tag as it has dependency in class , also i cannot modify css for it as it gets break on every page.if solution can be done using jquery then most welcome. thank you in advance.

JSP Code

<div class="fbox3 nspan">
<form:checkbox path="sendWelcomeEmail"  cssClass="label-revert" checked="true"label="Send a welcome email with login details to the user.  /></div>