phpjs/functions/strings/strcspn.js

php.js offers community built php functions in javascript

function strcspn(str, mask, start, length) {
  // From: http://phpjs.org/functions
  // +   original by: Brett Zamir (http://brett-zamir.me)
  // *     example 1: strcspn('abcdefg123', '1234567890');
  // *     returns 1: 7
  // *     example 2: strcspn('123abc', '1234567890');
  // *     returns 2: 3
  start = start ? start : 0;
  var count = (length && ((start + length) < str.length)) ? start + length : str.length;
  strct: for (var i = start, lgth = 0; i < count; i++) {
    for (var j = 0; j < mask.length; j++) {
      if (str.charAt(i).indexOf(mask[j]) !== -1) {
        continue strct;
      }
    } ++lgth;
  }

  return lgth;
}