function elementHasClass(el,cl){return (el.className&&el.className.search(new RegExp('\\b'+cl+'\\b'))>-1);}

function elementAddClass(el,cl){var c=el.className;if(!c)c='';if(!elementHasClass(el,cl))c+=((c.length>0)?' ':'')+cl;el.className=c;}

function elementRemoveClass(el,cl){if(el.className)el.className=el.className.replace(new RegExp('\\s*\\b'+cl+'\\b\\s*'),' ').replace(/^\s*/,'').replace(/\s*$/,'');}