Need help with script optimization

[YenRaven]

I have wrote a script that searches through the body's innerHTML to find and highlight each instance string omiting any matches in html tags. it works.. but slowly to the point that if you have more than about 100 matches it hangs up and crashes. I have tested the script in FireFox 1.5 only so i dont know how well it will work in IE. I was wondering if anyone knows any ways I could optimize this script to get it to run smoother. Here it is brace yourself...

function searchString(){
if(document.getElementById("search").value != ""){ //Check to see if there is a value in the search bar

var currIndex = 0
var searchText = document.getElementById("search").value.toLowerCas e(); //grab serach string from search bar.

do {
var bodyHTML = document.body.innerHTML //grab a copy of html so we dont return any formated highlighted text
var bodytext = document.body.innerHTML.toLowerCase(); //grab a formated copy of the html for case insentive searching.
if((bodytext.indexOf("<", bodytext.indexOf(searchText, currIndex)) < bodytext.indexOf(">", bodytext.indexOf(searchText, currIndex)) || bodytext.lastIndexOf(">", bodytext.indexOf(searchText, currIndex)) > bodytext.lastIndexOf("<", bodytext.indexOf(searchText, currIndex))) && (bodytext.charAt(bodytext.indexOf(searchText, currIndex)) != "<" && bodytext.charAt(bodytext.indexOf(searchText, currIndex)) != ">") && bodytext.indexOf(searchText, currIndex) > -1){ //This massive if statement checks to see if the next instance of the search string is inside a html statement.

var replaceString = "<font style='background-color:#ffff00;'>"+ bodyHTML.substr(bodytext.indexOf(searchText, currIndex), searchText.length) +"</font>"; //compiles the string to replace the found string with.
document.body.innerHTML = bodyHTML.substring(0, bodytext.indexOf(searchText, currIndex))+ replaceString +bodyHTML.substr(bodytext.indexOf(searchText, currIndex) + searchText.length) //replace the string.

currIndex = bodytext.indexOf(searchText, currIndex) + replaceString.length; //move the index in front of the last instance found.
}else{
currIndex = bodytext.indexOf(searchText, currIndex) + 1 //move the index beyond the last instance found.
}
}while(document.body.innerHTML.toLowerCase().index Of(searchText, currIndex) > -1); //do while the search string exists beyond the current index.
}
}

[YenRaven]

sry im a dufus this might look a little better.

function searchString(){
if(document.getElementById("search").value != ""){ //Check to see if there is a value in the search bar
 
var currIndex = 0
var searchText = document.getElementById("search").value.toLowerCase(); //grab serach string from search bar.
 
do {
var bodyHTML = document.body.innerHTML //grab a copy of html so we dont return any formated highlighted text
var bodytext = document.body.innerHTML.toLowerCase(); //grab a formated copy of the html for case insentive searching.
if((bodytext.indexOf("<", bodytext.indexOf(searchText, currIndex)) < bodytext.indexOf(">", bodytext.indexOf(searchText, currIndex)) || bodytext.lastIndexOf(">", bodytext.indexOf(searchText, currIndex)) > bodytext.lastIndexOf("<", bodytext.indexOf(searchText, currIndex))) && (bodytext.charAt(bodytext.indexOf(searchText, currIndex)) != "<" && bodytext.charAt(bodytext.indexOf(searchText, currIndex)) != ">") && bodytext.indexOf(searchText, currIndex) > -1){ //This massive if statement checks to see if the next instance of the search string is inside a html statement.
 
var replaceString = "<font style='background-color:#ffff00;'>"+ bodyHTML.substr(bodytext.indexOf(searchText, currIndex), searchText.length) +"</font>"; //compiles the string to replace the found string with.
document.body.innerHTML = bodyHTML.substring(0, bodytext.indexOf(searchText, currIndex))+ replaceString +bodyHTML.substr(bodytext.indexOf(searchText, currIndex) + searchText.length) //replace the string.
 
currIndex = bodytext.indexOf(searchText, currIndex) + replaceString.length; //move the index in front of the last instance found.
}else{
currIndex = bodytext.indexOf(searchText, currIndex) + 1 //move the index beyond the last instance found.
}
}while(document.body.innerHTML.toLowerCase().index Of(searchText, currIndex) > -1); //do while the search string exists beyond the current index.
}
}