Function for inserting some content (thread) after a marker(needle) inside a container (haystack). haystack should be and object.

insert_after.js

function insert_after(haystack, needle, thread)
{

                var browser=navigator.userAgent;

                if((typeof haystack.innerText == 'undefined') || (!(browser.indexOf("MSIE")>0)))
                {
                        var haystackText = haystack.innerHTML; 
                }
                else
                {
                        var haystackText = haystack.innerText;
                }
                var index=haystackText.indexOf(needle); 

                var bgnText = haystackText.substr(0,index+needle.length+1);
                var endText = haystackText.substr(index+needle.length,haystackText.length);
 
                if((typeof haystack.innerText == 'undefined') || (!(browser.indexOf("MSIE")>0)))
                {
                        haystack.innerHTML =  bgnText + thread + endText;
                }
                else
                {
                        haystack.innerText = bgnText + thread + endText;
                }
}

This function works (tested) with IE8, FF3.6, Safari 5, Chrome 8 on Linux and Windows.