replace and Highlight single word or letter in node type 3

replace and Highlight single word or letter in node type 3

Hi,

I'm trying to Highlight words in an iframe like this:

$('p',$('iframe').contents()).each(function(){
$(this).find("* :contains('subject')").each(function(){

return this.nodeType==3;
}).html(html().replace('subject','<span style=background-color:yellow>subject</span>'));
         
       });

I want to replace a letter or entire word with itself highlighted, but not having great results,

Regards