Question

Sometime back i had asked question in SO as to how to validate startdate < enddate.

The JS that i had written is as below;

function DateValidation(startDate, endDate) {
                if (startDate != ' ' && endDate != ' ') 
                {
                    var stdate = Date.parse(startDate);
                    var enddate = Date.parse(endDate);
                    if (stdate > enddate) 
                    {
                        alert('Start date cannot be greater than end date!');
                        return false;
                    }
                    else 
                {
                    return true;
                }
               }
            }

The function gets called on the click of the submit button. It is register as;

OnClientClick="javascript: return DateValidation(window.document.getElementById('txtStartDate').value,window.document.getElementById('txtEndDate').value);"

Now assume that start date is October 4 2011 (04/10/2011) and end date is December 2 2011 (02/12/2011). In this case the alert should NOT get fired but it still gets fired up (because 04 > 02).

What mistake am i making here?

Answer 1

Your startDate & endDate parameters should be in mm/dd/yyyy format. But you provided them as dd/mm/yyyy format, so the unexpected thing occured.

I’ve faced this kinda probs B4. If your website’s clients are all about to type in date time in format “dd/mm/yyyy”, so you need a “correctDate()” function to replace date part with month part in the input-date-string.

The function may look like this :

function correctDate(D){
       var D=D.split('/');
       return D[1]+'/'+D[0]+'/'+D[2]
}
//input :  2/10/2011 , output :  10/2/2011

And in the DateValidation() function, you can use it like this:

....
      var stdate = Date.parse( correctDate(startDate) );
      var enddate = Date.parse( correctDate(endDate) );
      if (stdate > enddate){
....