function checkValue (input) {
		if(input.value==input.defaultValue)
			input.value="";
		else if(input.value=="")
			input.value=input.defaultValue;
	}
	
	function hasClass(ele,cls) {
		return ele.className.match(new RegExp('(\\s|^)'+cls+'(\\s|$)'));
	}
	 
	function addClass(ele,cls) {
		if (!this.hasClass(ele,cls)) ele.className += " "+cls;
	}
	 
	function removeClass(ele,cls) {
		if (hasClass(ele,cls)) {
	    	var reg = new RegExp('(\\s|^)'+cls+'(\\s|$)');
			ele.className=ele.className.replace(reg,'');
		}
	}
	
	function switchTabs (sourceTab, otherTab, from, to) {
		if(hasClass(sourceTab, "activeTab"))
			return false;
		else{
			removeClass(document.getElementById(otherTab), "activeTab");
			addClass(document.getElementById(otherTab), "inactiveTab");
			removeClass(sourceTab, "inactiveTab");
			addClass(sourceTab, "activeTab");
			document.getElementById(from).style.display='none';
			document.getElementById(to).style.display='block';
		}
	}