i made this script that may help you.
open the webpage you want to audit, paste the code below to the address bar after the web page is fully loaded. I tested it in Google Chrome
javascript:var elts=new Array("tag1","tag2","tag3",....,"tagn"");var n=elts.length;var sum=0;var i;for(i=0;i<n;i++){sum += document.getElementsByTagName(elts).length};alert(sum);
USAGE- in the first line replace the italics part with the name of the HTML tags(in quotes) separated by commas you want to audit. then paste it to the browser Address bar. Eg if you want to count the number of images(img), div and body(ITS JUST FOR EXAMPLE), modify the code as
javascript:var elts=new Array("img","div","body");var n=elts.length;var sum=0;var i;for(i=0;i<n;i++){sum += document.getElementsByTagName(elts).length};alert(sum);