JavaScript - Problemilla con un tooltop

<STYLE>

   /*  This is for Netscape 4.0+ broswsers so that the border will display.  If you want to modify the background color this is where you would do it for NS4.0+.  To modify the color for IE and NS6 do so in the style tag in the div below

   */

   .ttip {border:1px solid black;font-size:12px;layer-background-color:lightyellow;background-color:lightyellow}

</STYLE>

<script>

//Script created by Jim Young (www.requestcode.com)

//Submitted to JavaScript Kit (http://javascriptkit.com)

//Visit http://javascriptkit.com for this script

//Set the tool tip message you want for each link here.

     var tip=new Array

           tip[0]='Visit Dynamic Drive<br> for DHTML Scripts!'

           tip[1]='Visit JavaScript Kit for Great<br> Scripts, Tutorials and Forums!'

           tip[2]='Visit Request Code for FREE JavaScripts!'

           tip[3]='Click here for some excellent<br>Java applets and tutorials'

     function showtip(current,e,texto)

        {

         if (document.layers) // Netscape 4.0+

            {

             theString="<DIV CLASS='ttip'>"+tip[num]+"</DIV>"

             document.tooltip.document.write(theString)

             document.tooltip.document.close()

             document.toolti