Simple jQuery table of contents generator. Scans page for <h2> headings, adds IDs to those headings that don't have any and then prepends a Table of contents to the page.

gistfile1.js

// Assumes availability of jQuery...

function generate_toc() {
    // Get the headings
    var body = $('body');
    var headings =  body.find('h2');
    
    // We don't need a table of contents if we don't have any headings
    if (headings.length == 0) return false;        

    // Setup the div#toc  
    var toc = $('<div class="toc"><ul></ul></div>');

    // Setup the div#toc h3 & div#toc ul
	
    headings.each(function(heading) {
    	// Get the existing heading id or setup a new one based on the heading text
        var title = heading.text();

        // If the heading doesn't have an id attribute we need to make one up
        if(!heading.attr("id")) {
          // We'll lowercase the heading text, remove any white space and make that the id
          heading.attr('id',title.toLowerCase().replace(/\W/g,''));
        }

        // Add a li element with anchor link to the heading
        toc.find('ul').append('<a href="#'+heading.attr('id')+'>'+content+'</a>');
    });

    // Add our link to the top anchor
    toc.find('ul').append('<a href="#top">Top</a>');

    // Prepend our TOC to the document
    body.prepend(toc);
    
    // Put a top anchor at the very beginning of the document
    body.prepend('<a id="#top"></a>');
    
    // Check if there's already a anchor hash - scroll there if needed
    // This will make sure that bookmarks with anchors will behave as expected
    if(window.location.hash.length > 0) {
        $('html, body').animate({
            scrollTop: $(window.location.hash).offset();
        }, 2000);
    }
}

$(document).ready(function(){
    generate_toc();
});