Jak na nahrazení textu s ignorováním tagů

var text_hledany='spa';
var text_vzor =text_hledany+'(?![^<>]*>)'; 
var text_nahradni = '<span class="hightlight">'+text_hledany+'<\/span>'; 
var text_prohledavany = '<span class="space">Spal jsem ve spacím pytli.<\/span>'; 
var text_novy = text_prohledavany.replace(new RegExp(text_vzor,'ig'),text_nahradni); 

<meta http-equiv="Content-Type" content="text/html; charset=utf-8">
<script>
function bla(){ 
var text_hledany='spa';
var text_vzor =text_hledany+'(?![^<>]*>)'; 
var text_nahradni = '<span class="hightlight">'+text_hledany+'<\/span>'; 
var text_prohledavany = '<span class="space">Spal jsem ve spacím pytli.<\/span>'; 
var text_novy = text_prohledavany.replace(new RegExp(text_vzor,'ig'),text_nahradni); 
alert(text_novy)
}
window.onload=bla;
</script>

var text_nahradni = '<span class="hightlight">$&<\/span>';

<style type="text/css">
.hightlight{font-weight:bold;color:red;}
</style>
<form action="#" id="form">
<input type="text" id="query" value="lorem">
<input type="submit" value="Search and highlight">
</form>
<div id="scanned">
Lorem ipsum dolor sit amet, consectetuer adipiscing elit, sed diam nonummy nibh euismod tincidunt ut laoreet dolore magna aliquam erat volutpat. Ut wisi enim ad minim veniam, quis nostrud exerci tation ullamcorper suscipit lobortis nisl ut aliquip ex ea commodo consequat. Duis autem vel eum iriure dolor in hendrerit in vulputate velit esse molestie consequat, vel illum dolore eu feugiat nulla facilisis at vero eros et accumsan et iusto odio dignissim qui blandit praesent luptatum zzril delenit augue duis dolore te feugait nulla facilisi. Nam liber tempor cum soluta nobis eleifend option congue nihil imperdiet doming id quod mazim placerat facer possim assum. Typi non habent claritatem insitam; est usus legentis in iis qui facit eorum claritatem. Investigationes demonstraverunt lectores legere me lius quod ii legunt saepius. Claritas est etiam processus dynamicus, qui sequitur mutationem consuetudium lectorum. Mirum est notare quam littera gothica, quam nunc putamus parum claram, anteposuerit litterarum formas humanitatis per seacula quarta decima et quinta decima. Eodem modo typi, qui nunc nobis videntur parum clari, fiant sollemnes in futurum.
</div>
<script type="text/javascript">
function hightligth_search_query(){
document.getElementById('form').onsubmit=function(){
var scanned=document.getElementById('scanned').innerHTML; 
if(document.uniqueID){var remove_replacement='<SPAN class=hightlight>([^<]*)</SPAN>';}
else{var remove_replacement='<span class="hightlight">([^<]*)</span>';}
var new_scanned=scanned.replace(new RegExp(remove_replacement,'ig'),'$1'); 
document.getElementById('scanned').innerHTML=new_scanned;
var sq=document.getElementById('query').value;
var pattern=sq+'(?![^<>]*>)'; 
var replacement='<span class="hightlight">$&</span>'; 
var result=new_scanned.replace(new RegExp(pattern,'ig'),replacement); 
document.getElementById('scanned').innerHTML=result;
return false;
};
}
window.onload=hightligth_search_query;
</script>

if(document.uniqueID){var remove_replacement='<SPAN class=hightlight>([^<]*)</SPAN>';}//msie
else{var remove_replacement='<span class="hightlight">([^<]*)</span>';}//ostatni