Comment créer un moteur de recherche ?

<script>
<!-- Hide from old browsers

/******************************************
* Find In Page Script -- Submitted/revised by Alan Koontz (alankoontz@REMOVETHISyahoo.com)
* Visit Dynamic Drive (http://www.dynamicdrive.com/) for full source code
* This notice must stay intact for use
******************************************/

//  revised by Alan Koontz -- May 2003

var TRange = null;
var dupeRange = null;
var TestRange = null;
var win = null;


//  SELECTED BROWSER SNIFFER COMPONENTS DOCUMENTED AT
//  http://www.mozilla.org/docs/web-developer/sniffer/browser_type.html

var nom = navigator.appName.toLowerCase();
var agt = navigator.userAgent.toLowerCase();
var is_major   = parseInt(navigator.appVersion);
var is_minor   = parseFloat(navigator.appVersion);
var is_ie      = (agt.indexOf("msie") != -1);
var is_ie4up   = (is_ie && (is_major >= 4));
var is_not_moz = (agt.indexOf('netscape')!=-1)
var is_nav     = (nom.indexOf('netscape')!=-1);
var is_nav4    = (is_nav && (is_major == 4));
var is_mac     = (agt.indexOf("mac")!=-1);
var is_gecko   = (agt.indexOf('gecko') != -1);
var is_opera   = (agt.indexOf("opera") != -1);


//  GECKO REVISION

var is_rev=0
if (is_gecko) {
temp = agt.split("rv:")
is_rev = parseFloat(temp[1])
}


//  USE THE FOLLOWING VARIABLE TO CONFIGURE FRAMES TO SEARCH
//  (SELF OR CHILD FRAME)

//  If you want to search another frame, change from "self" to
//  the name of the target frame:
//  e.g., var frametosearch = 'main'

//var frametosearch = 'main';
var frametosearch = self;


function search(whichform, whichframe) {

//  TEST FOR IE5 FOR MAC (NO DOCUMENTATION)

if (is_ie4up && is_mac) return;

//  TEST FOR NAV 6 (NO DOCUMENTATION)

if (is_gecko && (is_rev <1)) return;

//  TEST FOR Opera (NO DOCUMENTATION)

if (is_opera) return;

//  INITIALIZATIONS FOR FIND-IN-PAGE SEARCHES

if(whichform.findthis.value!=null && whichform.findthis.value!='') {

       str = whichform.findthis.value;
       win = whichframe;
       var frameval=false;
       if(win!=self)
{

       frameval=true;  // this will enable Nav7 to search child frame
       win = parent.frames[whichframe];

}

    
}

else return;  //  i.e., no search string was entered

var strFound;

//  NAVIGATOR 4 SPECIFIC CODE

if(is_nav4 && (is_minor < 5)) {
   
  strFound=win.find(str); // case insensitive, forward search by default

//  There are 3 arguments available:
//  searchString: type string and it's the item to be searched
//  caseSensitive: boolean -- is search case sensitive?
//  backwards: boolean --should we also search backwards?
//  strFound=win.find(str, false, false) is the explicit
//  version of the above
//  The Mac version of Nav4 has wrapAround, but
//  cannot be specified in JS

 
        }

//  NAVIGATOR 7 and Mozilla rev 1+ SPECIFIC CODE (WILL NOT WORK WITH NAVIGATOR 6)

if (is_gecko && (is_rev >= 1)) {
   
    if(frameval!=false) win.focus(); // force search in specified child frame
    strFound=win.find(str, false, false, true, false, frameval, false);

//  The following statement enables reversion of focus 
//  back to the search box after each search event 
//  allowing the user to press the ENTER key instead
//  of clicking the search button to continue search.
//  Note: tends to be buggy in Mozilla as of 1.3.1
//  (see www.mozilla.org) so is excluded from users 
//  of that browser.

    if (is_not_moz)  whichform.findthis.focus();

//  There are 7 arguments available:
//  searchString: type string and it's the item to be searched
//  caseSensitive: boolean -- is search case sensitive?
//  backwards: boolean --should we also search backwards?
//  wrapAround: boolean -- should we wrap the search?
//  wholeWord: boolean: should we search only for whole words
//  searchInFrames: boolean -- should we search in frames?
//  showDialog: boolean -- should we show the Find Dialog?


}

 if (is_ie4up) {

  // EXPLORER-SPECIFIC CODE revised 5/21/03

  if (TRange!=null) {
	  
   TestRange=win.document.body.createTextRange();
 
	  

   if (dupeRange.inRange(TestRange)) {

   TRange.collapse(false);
   strFound=TRange.findText(str);
    if (strFound) {
        //the following line added by Mike and Susan Keenan, 7 June 2003
        win.document.body.scrollTop = win.document.body.scrollTop + TRange.offsetTop;
        TRange.select();
        }


   }
   
   else {

     TRange=win.document.body.createTextRange();
     TRange.collapse(false);
     strFound=TRange.findText(str);
     if (strFound) {
        //the following line added by Mike and Susan Keenan, 7 June 2003
        win.document.body.scrollTop = TRange.offsetTop;
        TRange.select();
        }



   }
  }
  
   if (TRange==null || strFound==0) {
   TRange=win.document.body.createTextRange();
   dupeRange = TRange.duplicate();
   strFound=TRange.findText(str);
    if (strFound) {
        //the following line added by Mike and Susan Keenan, 7 June 2003
        win.document.body.scrollTop = TRange.offsetTop;
        TRange.select();
        }

   
   }

 }

  if (!strFound) alert ("String '"+str+"' not found!") // string not found

        
}
// -->
</script>

<!--  EXAMPLE FORM OF FIND-IN-PAGE SEARCH USING SUBMIT (ALLOWING 'ENTER/RETURN' KEY PRESS EVENT) -->
<form name="form1" onSubmit="search(document.form1, frametosearch); return false"><input type="text" name="findthis" size="15" title="Press 'ALT s' after clicking submit to repeatedly search page"> <input type="submit" value="Find in Page" ACCESSKEY="s"></form>

if (!strFound) alert ("String '"+str+"' not found!")