/*
* This is the function that actually highlights a text string by
* adding HTML tags before and after all occurrences of the search
* term. You can pass your own tags if you'd like, or if the
* highlightStartTag or highlightEndTag parameters are omitted or
* are empty strings then the default <font> tags will be used.
*/
function doHighlight(bodyText, searchTerm, highlightStartTag, highlightEndTag)
{
// the highlightStartTag and highlightEndTag parameters are optional
if ((!highlightStartTag) || (!highlightEndTag)) {
highlightStartTag = "<font style='color:blue; background-color:yellow;'>";
highlightEndTag = "</font>";
}
// find all occurences of the search term in the given text,
// and add some "highlight" tags to them (we're not using a
// regular expression search, because we want to filter out
// matches that occur within HTML tags and script blocks, so
// we have to do a little extra validation)
var newText = "";
var i = -1;
var lcSearchTerm = searchTerm.toLowerCase();
var lcBodyText = bodyText.toLowerCase();
while (bodyText.length > 0) {
i = lcBodyText.indexOf(lcSearchTerm, i+1);
if (i < 0) {
newText += bodyText;
bodyText = "";
} else {
// skip anything inside an HTML tag
if (bodyText.lastIndexOf(">", i) >= bodyText.lastIndexOf("<", i)) {
// skip anything inside a <script> block
if (lcBodyText.lastIndexOf("/script>", i) >= lcBodyText.lastIndexOf("<script", i)) {
newText += bodyText.substring(0, i) + highlightStartTag + bodyText.substr(i, searchTerm.length) + highlightEndTag;
bodyText = bodyText.substr(i + searchTerm.length);
lcBodyText = bodyText.toLowerCase();
i = -1;
}
}
}
}
return newText;
}
/*
* This is sort of a wrapper function to the doHighlight function.
* It takes the searchText that you pass, optionally splits it into
* separate words, and transforms the text on the current web page.
* Only the "searchText" parameter is required; all other parameters
* are optional and can be omitted.
*/
function highlightSearchTerms(elementToSearch, searchText, treatAsPhrase, warnOnFailure, highlightStartTag, highlightEndTag)
{
// if the treatAsPhrase parameter is true, then we should search for
// the entire phrase that was entered; otherwise, we will split the
// search string so that each word is searched for and highlighted
// individually
if (treatAsPhrase) {
searchArray = [searchText];
} else {
searchArray = searchText.split(" ");
}
if (!document.body || typeof(document.body.innerHTML) == "undefined") {
if (warnOnFailure) {
alert("Sorry, for some reason the text of this page is unavailable. Searching will not work.");
}
return false;
}
//var bodyText = document.body.innerHTML;
var bodyText = document.getElementById(elementToSearch).innerHTML;
for (var i = 0; i < searchArray.length; i++) {
bodyText = doHighlight(bodyText, searchArray[i], highlightStartTag, highlightEndTag);
}
document.getElementById(elementToSearch).innerHTML = bodyText;
return true;
}