var included_files = null;

function js_include($script) {
    if (document.getElementsByTagName) {
	if (!included_files) {
	    included_files = {};
	    var cScripts = document.getElementsByTagName("script");
	    for (var i=0,len=cScripts.length; i < len; i++)
		if (cScripts[i].src) included_files[cScripts[i].src] = true;
	}

	if(!included_files[$script]) {
	    var script = document.createElement('script');
	    script.src = $script;
	    script.type = 'text/javascript';
	    document.getElementsByTagName('head').item(0).appendChild(script);
	
	    included_files[$script] = true;
	}
      }
}

//Main AJAX Library
js_include("javascript/scriptaculous/scriptaculous.js");