<script src="https://ajax.googleapis.com/ajax/libs/jquery/1.7.1/jquery.min.js"></script>
<script type="text/javascript">
var jQ = $.noConflict(true);
jQ(document).ready(function(){
//The inputs you want read only
jQ('input[name^="ranking"]').attr('readonly', true);

//inputs that will need to be calculated
jQ('input[name^="g"]').addClass('cal');
jQ('input[name^="crg"]').addClass('cal');

//Trigger on key
jQ('.cal').bind('keyup blur change',function(){
var jQnonempty = jQ('.cal').filter(function() {
return this.value != ''
});
if (jQnonempty.length !== 0) {
// Set variables for each input by name
var g1 = jQ('input[name="g1"]').val();
var g2 = jQ('input[name="g2"]').val();
var g3 = jQ('input[name="g3"]').val();
var crg1 = jQ('input[name="crg1"]').val();
var crg2 = jQ('input[name="crg2"]').val();
var crg3 = jQ('input[name="crg3"]').val();
//501 game avg.
var gavg = (+g1 + +g2 + +g3)/3;
// Cricket Game avg.
var crgavg = (+crg1 + +crg2 + +crg3)/3;
//Ranking
var ranking = gavg + crgavg;

jQ('input[name="ranking"]').val(ranking.toFixed(2));
}

});

});</script>