Hi,
Try this code for your checkbox:
function checkValidity()
{
var status = $('#chkTerms').is(':checked');
if(status==false)
{
alert('Check Terms and Conditions');
return false;
}
else
{
return true;
}
}
And on clientClick of the button pass this javascript function to check the values.
OnClientClick="return checkValidity();"
Change your functin as per your requirements.
Hope this helps !! :)
Regards,
Praneet