Procura de palavras na página

<script LANGUAGE="JavaScript">
<!-- Web Site: http://members.aol.com/MHall75819 -->
<!-- This script and many more are available free online at -->
<!-- The JavaScript Source!! http://javascript.internet.com --> 

<!-- Begin
var NS4 = (document.layers);
var IE4 = (document.all);

var win = this;
var n = 0;

function findInPage(str) {
var txt, i, found;
if (str == "")
return false;
if (NS4) {
if (!win.find(str))
while(win.find(str, false, true))
n++;
else
n++;
if (n == 0) alert(str + " was not found on this page.");
}
if (IE4) {
txt = win.document.body.createTextRange();
for (i = 0; i <= n &amp;&amp; (found = txt.findText(str)) != false; i++) {
txt.moveStart("character", 1);
txt.moveEnd("textedit");
}
if (found) {
txt.moveStart("character", -1);
txt.findText(str);
txt.select();
txt.scrollIntoView();
n++;
}
else {
if (n > 0) {
n = 0;
findInPage(str);
}
else
alert(str + " was not found on this page.");
}
}
return false;
}
// End -->
</script>
<!-- STEP TWO: Copy this code into the BODY of your HTML document -->
<form name="search" onSubmit="return findInPage(this.string.value);">
Procura na página <input name="string" type="text" size="15" onChange="n = 0;" value="Digite a palavra procurada e aperte enter">
</form>