Fechas

[Campeon2]

Hola a todo el mundo!!!
Como puedo saber si una fecha es válida??, algo así como el Isdate de Visual.

[Mickel]

de Javascripts.internet.com

Código:

<script language='JavaScript'>
<!--
var isNav4 = false, isNav5 = false, isIE4 = false
var strSeperator = "/"; 
var vDateType = 3;
var vYearType = 4;
var vYearLength = 4;
var err = 0;
if(navigator.appName == "Netscape") {
	if (navigator.appVersion < "5") {
		isNav4 = true;
		isNav5 = false;
	} else 
		if (navigator.appVersion > "4") {
			isNav4 = false;
			isNav5 = true;
		}
} else {
	isIE4 = true;
}

function DateFormat(vDateName, vDateValue, e, dateCheck, dateType) {
vDateType = dateType;
// vDateName = object name
// vDateValue = value in the field being checked
// e = event
// dateCheck 
// True  = Verify that the vDateValue is a valid date
// False = Format values being entered into vDateValue only
// vDateType
// 1 = mm/dd/yyyy
// 2 = yyyy/mm/dd
// 3 = dd/mm/yyyy
//Enter a tilde sign for the first number and you can check the variable information.
if (vDateValue == "~") {
alert("AppVersion = "+navigator.appVersion+" \nNav. 4 Version = "+isNav4+" \nNav. 5 Version = "+isNav5+" \nIE Version = "+isIE4+" \nYear Type = "+vYearType+" \nDate Type = "+vDateType+" \nSeparator = "+strSeperator);
vDateName.value = "";
vDateName.focus();
return true;
}
var whichCode = (window.Event) ? e.which : e.keyCode;
// Check to see if a seperator is already present.
// bypass the date if a seperator is present and the length greater than 8
if (vDateValue.length > 8 && isNav4) {
if ((vDateValue.indexOf("-") >= 1) || (vDateValue.indexOf("/") >= 1))
return true;
}
//Eliminate all the ASCII codes that are not valid
var alphaCheck = " abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ/-";
if (alphaCheck.indexOf(vDateValue) >= 1) {
if (isNav4) {
vDateName.value = "";
vDateName.focus();
vDateName.select();
return false;
}
else {
vDateName.value = vDateName.value.substr(0, (vDateValue.length-1));
return false;
   }
}
if (whichCode == 8)
return false;
else {
// -->
</script>