Remove leading zeros of a string in Javascript

s.replace(/\b0+[1-9]\d*/g, '')

should replace any zeros that are after a word boundary and before a non-zero digit. That is what I think you're looking for here.

The simplest solution would probably be to use a word boundary (\b) like this:

s.replace(/\b0+/g, '')

This will remove any zeros that are not preceded by Latin letters, decimal digits, underscores. The global (g) flag is used to replace multiple matches (without that it would only replace the first match found).

$("button").click(function() {
  var s = $("input").val();
  
  s = s.replace(/\b0+/g, '');
  
  $("#out").text(s);
});

body { font-family: monospace; }
div { padding: .5em 0; }
#out { font-weight: bold; }

<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script>
<div><input value="02-03, 02&03, 02,03"><button>Go</button></div>
<div>Output: <span id="out"></span></div>