Is Date

behöver en koll om de har skrivit in ett giltigt datum enligt yyyy-mm-dd

har idag denna koden

function addOption(optText,frm_name,lstBox_name)
{	
	var optValue = document.forms[frm_name].elements[optText].value;

	if (optValue != '')
	{
		var Box = document.forms[frm_name].elements[lstBox_name];
		var i = 0;
		var test = true;
		while(i<Box.options.length)
	{
	if (Box.options[i].value == optValue) {test = false; break;}
		i++;
		}
	if (test)
	{
		var newOption = new Option(optValue,optValue);
		var Box = document.forms[frm_name].elements[lstBox_name];
		Box.options[Box.options.length] = newOption;
	}
	else
	{
		alert('You have already choice that date!');
	}
	}
	else
	{
		alert('You have to select a date!');
	}
		return false;
}

vill göra en koll på variablen "optValue"

[red]String.prototype.isValidDate = function(){
	if(!this.match(/^(\d{4})\-(\d{2})\-(\d{2})$/)){ return false; }
	return (RegExp.$3<=new Date(RegExp.$1,RegExp.$2,0).getDate()&&RegExp.$3>0&&RegExp.$2<13&&RegExp.$2>0);
}[/red]
function addOption(optText,frm_name,lstBox_name)
{	
	var optValue = document.forms[frm_name].elements[optText].value;

	if (optValue != '')
	{
		[red]if(!optValue.isValidDate()){ alert('Date is invalid'); return false; }[/red]
		var Box = document.forms[frm_name].elements[lstBox_name];
		var i = 0;
		var test = true;
		while(i<Box.options.length)
	{
	if (Box.options[i].value == optValue) {test = false; break;}
		i++;
		}
	if (test)
	{
		var newOption = new Option(optValue,optValue);
		var Box = document.forms[frm_name].elements[lstBox_name];
		Box.options[Box.options.length] = newOption;
	}
	else
	{
		alert('You have already choice that date!');
	}
	}
	else
	{
		alert('You have to select a date!');
	}
		return false;
}

Tillagd kod markerad.