jquery - Clear array and text box with javascript -

each time checkbox checked, below function called. problem need function should clear data available here.

let me explain problem first:

the concept of program update text box checkbox value - if 2 check boxes checked, text box have 2 values in , on.

i need function clear data on check box when click 3rd check box needs show 3rd checkbox's value removing first , second text area. should happen without reloading page

<script>     function chkcontrol(j){         var textbox = document.getelementbyid("list");         var textbox1 = document.getelementbyid("val_id");         var values = [];             var val_id=[];         if(document.getelementbyid(1).checked) {             values.push('a1');             val_id.push('1');         }         if(document.getelementbyid(2).checked) {             values.push('a2');             val_id.push('2');   }         if(document.getelementbyid(3).checked) {             values.push("a3");             val_id.push('3');         }         if(document.getelementbyid(4).checked) {             values.push("a4");             val_id.push('4');         }         if(document.getelementbyid(5).checked) {             values.push("a5");             val_id.push('5');         }         if(document.getelementbyid(6).checked) {             values.push("a6");             val_id.push('6');         }          textbox.value = values.join(",");         textbox1.value = val_id.join(",");     }      function removeall(){     } </script>  <input id="list" type="text" name="list"> <input id="val_id" type="text" name="val_id"> <input type="checkbox" name="ckb" value="a1" id="1" onclick='chkcontrol(0)';> <label for="1"></label> <input type="checkbox" name="ckb" value="a2" id="2" onclick='chkcontrol(0)';> <label for="2"></label> <input type="checkbox" name="ckb" value="a3" id="3" onclick='chkcontrol(0)';> <label for="3"></label> 

i don't know need here, if need "clear" javascript array set length 0 (zero).

var = [0,1,2,3,4,5,6,7,8,9]; a.length = 0; // truncate array 

mdn says: "you can set length property truncate array @ time."

hope helps you...