How can I get the url value after a question mark in javascript?

I want the following behaviour:

if value is yes then 10+2 

else if value is no then 10.

I want to output with alert messages.

<div class=col-xs-4 col-sm-4 col-md-4 text-center width100>

    <a href=piccal.html class=btn btn-success id=yes>PIC Grant Calculator</a>

</div>

<div class=col-xs-4 col-sm-4 col-md-4 text-center width100>

    <a href=piccal.html class=btn btn-danger id=no>PIC Grant Calculator</a>

</div>



<script> 

if (value == no) {

    alert('hello');

}

</script>



<script> 

if (value == yes) {

    alert('hi');

}

</script>