javascript - How to add `0` this kind of condition in code? -

i have code below working fine trying if input 5:30 code auto add 0 output 05:30.

i try edit code jsfiddle 2 failed it.

is possible want output be?.

html :

    <div>     <input id="departure" type="text" style="width: 50px; text-align: center" placeholder="00:00" maxlength = "5" />     </div> 

javascript :

    <script type="text/javascript">     document.getelementbyid('departure').addeventlistener('keyup',         function(event) {             if(event.target.value.length === 2) {             if((event.key && !isnan(event.key)) || (event.keycode >= 48 && event.keycode <= 57)) {           if(!isnan(event.target.value) && parseint(event.target.value) > 12) {           event.target.value = event.target.value.slice(0,1) + ':' + event.target.value.substring(1);           } else {                 event.target.value += ':';           }         }       }     }); </script> 

jsfiddle

jsfiddle 2

you can try this:

'0' + event.target.value.slice(0,1).slice(-2) + ':' + '0' + event.target.value.substring(1).slice(-2) 

ie., can pad 0 @ beginning of value , slice 2 digits last.