请教一个jquery的问题

$(function() {

 jQuery.highlight = document.body.createTextRange ? 



/*

Version for IE using TextRanges.

*/

  function(node, te) {

   var r = document.body.createTextRange();

   r.moveToElementText(node);

   for (var i = 0; r.findText(te); i++) {

    r.pasteHTML('<b>' +  r.text + '<\/b>');

    r.collapse(false);

   }

  }



 :



/*

 (Complicated) version for Mozilla and Opera using span tags.

*/

  function(node, te) {

   var pos, skip, spannode, middlebit, endbit, middleclone;

   skip = 0;

   if (node.nodeType == 3) {

    pos = node.data.toUpperCase().indexOf(te);

    if (pos >= 0) {

     spannode = document.createElement('span');

     spannode.className = 'highlight';

     middlebit = node.splitText(pos);

     endbit = middlebit.splitText(te.length);

     middleclone = middlebit.cloneNode(true);

     spannode.appendChild(middleclone);

     middlebit.parentNode.replaceChild(spannode, middlebit);

     skip = 1;

    }

   }

   else if (node.nodeType == 1 && node.childNodes && !/(script|style)/i.test(node.tagName)) {

    for (var i = 0; i < node.childNodes.length; ++i) {

     i += $.highlight(node.childNodes[i], te);

    }

   }

   return skip;

  }



 ;

});



jQuery.fn.removeHighlight = function() {

 return this.find("span.highlight").each(function() {

  this.parentNode.replaceChild(this.firstChild, this).normalize();

 });

};