how to validate date field using jquery?

Here is a function to check valid date format as mentioned below :-

function IsValidDate(dtValue)
{
    var dtRegex = new RegExp(/\b\d{1,2}[\/-]\d{1,2}[\/-]\d  {4}\b/);
    return dtRegex.test(dtValue);
}

To Use this method on any date text field below is the code example :-

$(function() {
	$('.errorDiv').hide();
	$('#btnTest').click(function(event){
   		var dtVal=$('#txtDate').val();
   		if(IsValidDate(dtVal))	$('.errorDiv').hide();
   		else
   		{
     			$('.errorDiv').show();
     			event.preventDefault();
   		}
   	});
});

Here 'errorDiv' is the class name assigned to the div used for displaying the error message when date validation fails.

Hope this will be of help to you.