function checkInDatesValidation(source, clientside_arguments)
{
    var startDate;
    var endDate;
    var monthNames = ['January','February','March','April','May','June','July', 'August','September','October','November','December'];
 
    //StartDate
    if (typeof checkInDateFieldID != "undefined")
    {
        var startDateField = document.getElementById(checkInDateFieldID + "_dateInput_text");
        startDate = startDateField.value;
    }
    else
        startDate =  ((new Date()).getDate() + " " + monthNames[(new Date()).getMonth()] + " " + (new Date()).getYear());
        
    //EndDate 
    if (typeof checkOutDateFieldID != "undefined")
    {
        var endDateField=document.getElementById(checkOutDateFieldID + "_dateInput_text");       
        endDate= endDateField.value;
    }
    else
        startDate =  ((new Date()).getDate() + " " + monthNames[(new Date()).getMonth()] + " " + (new Date()).getYear());
    
    var startDateTime = new Date(startDate + " 00:00:00");
    var endDateTime = new Date(endDate + " 00:00:00");
    
    if (endDateTime < startDateTime)  
    {
        endDateField.focus();
        clientside_arguments.IsValid = false;
    }
    else
    {
        clientside_arguments.IsValid = true;
    }
}