IE web browser often won't handle indexOf() command in JavaScript (Jscript is IE's engine or coding for Jscript.net), so here is an alternate function: http://jsfiddle.net/ccxqosxn/

indexof-alternative.js

function myIndexOf(a, b) {
  var c, d, e = a.length, f = b.length;
  for (c = 0; e > c; c++) {
    for (d = 0; f > d && a[c + d] == b[d]; d++) ;
    if (d == f) return c;
  }
  return -1;
}

//USAGE:

//var str1ng='http://www.WHAK.com';

//alert(myIndexOf(str1ng, 'WHAK'));

//-1 response means that it is not found in string
//returns character position that found is located

Minified:

function myIndexOf(a,b){var c,d,e=a.length,f=b.length;for(c=0;e>c;c++){for(d=0;f>d&&a[c+d]==b[d];d++);if(d==f)return c}return-1}