DEMO : Limiting the Selection based on sum of value off checkboxes

JavaScript

<script type="text/javascript"> 
function chkcontrol(j) {
var sum=0;
for(var i=0; i < document.form1.ckb.length; i++){

if(document.form1.ckb[i].checked){
sum = sum + parseInt(document.form1.ckb[i].value);
}
document.getElementById("msg").innerHTML="Sum :"+ sum;

if(sum >10){
sum = sum - parseInt(document.form1.ckb[j].value);
document.form1.ckb[j].checked = false ;
alert("Sum of the selection can't be more than 10") 
//return false;
}
document.getElementById("msg").innerHTML="Sum :"+ sum;
}
}
</script>

HTML

<form name=form1 method=post action=check.php>

<table class='table table-striped' >
  
<tr ><th >Select</th></tr>
<tr ><td ><input type=checkbox name=ckb value=1 onclick='chkcontrol(0)';> Value = 1 </td></tr>
<tr><td ><input type=checkbox name=ckb value=2 onclick='chkcontrol(1)';> Value = 2 </td></tr>
<tr  ><td ><input type=checkbox name=ckb value=3 onclick='chkcontrol(2)';> Value = 3 </td></tr>
<tr ><td ><input type=checkbox name=ckb value=4 onclick='chkcontrol(3)';> Value = 4 </td></tr>
<tr  ><td ><input type=checkbox name=ckb value=5 onclick='chkcontrol(4)';> Value = 5 </td></tr>
<tr ><td ><input type=checkbox name=ckb value=6 onclick='chkcontrol(5)';> Value = 6 </td></tr>
<tr  ><td ><input type=checkbox name=ckb value=7 onclick='chkcontrol(6)';> Value = 7 </td></tr>
<tr ><td ><input type=checkbox name=ckb value=8 onclick='chkcontrol(7)';> Value = 8 </td>  </tr>
</table></form>
Sum of the values can't exceed 10. 
<br><br>
<div id=msg></div>