javascript - Specific value element input not read by -

i dont know if browser bug or else, because have tested on chrome , firefox. same result. tried input value element 1,10,100 identified. this's code.

html

<input id="items" type="text" placeholder="title" value=""> <input id="start" type="text" placeholder="start" value=""> <input id="end" type="text" placeholder="end" value=""> <input id="btn" type="submit" value="generate"><br><br> <div id="output" contenteditable="true"></div> 

javascript

<script>  var btn = document.getelementbyid('btn') var output = document.getelementbyid('output');  btn.addeventlistener('click', function(){  var items = document.getelementbyid('items').value; var = document.getelementbyid('start').value; var e = document.getelementbyid('end').value;  for(i; i<=e; i++){   output.innerhtml += items+'/'+i;  }  }, false);  </script> 

it not generate if start value input element not 1,10,100. how can make work? start 2,3,4,5,6,7,8,9?

you need convert values integers:

var = parseint( document.getelementbyid('start').value, 10 ); var e = parseint( document.getelementbyid('end').value, 10 );