This program compares three different ways to search for a string...

<SCRIPT>

STRING = "ZLKJASIOEIRUWEORILKZSDJFSDLFJKHSDJKFGSDJKHSDFKGHSDLABCACABC33DFJKLCBAABABXCABABCABCABCABC33A";

FIND_THIS = "ABCABCABC33";

temp = 0;
T1 = (new Date()).getTime();
document.write("<HR>start time = " + T1);

for (i = 0; i < 10000; i++)
{
  temp += STRING.indexOf(FIND_THIS);           // THIS IS THE FASTEST!
//  temp += STRING.split(FIND_THIS)[0].length; // SLOWER METHOD
//  temp += FindString(STRING, FIND_THIS);     // SLOWEST METHOD
}

T2 = (new Date()).getTime();

DIFF = T2 - T1;

document.write("<P>end time = " + T2 + "<P>difference = " + DIFF + " ms");

//
// This function is the same as the builtin indexOf() function, but
// this one is 100X slower in MSIE and 5X slower in Google Chrome.
// So, you should stick to using indexOf() instead.
// This is just for an illustration.
//
function FindString(STR, SUBSTR)
{
  var len = STR.length, sslen = SUBSTR.length;
  if (len == 0 || len < sslen || sslen == 0) return -1;
  var i = -1, c, MATCH, START, first = SUBSTR.charCodeAt(0);
  while (++i < len)
  {
    c = STR.charCodeAt(i);
    if (c != first) continue;
    if (sslen == 1) return i;
    START = i;
    MATCH = 1;
    for (j = 1; j < sslen; j++)
    {
      c = STR.charCodeAt(++i);
      if (c == SUBSTR.charCodeAt(j)) MATCH++; else break;
    }
    if (MATCH == sslen) return START; else i = START;
  }
  return -1;
}

</SCRIPT>