validating controls in mvc 3

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C#

C#4.0

MVC3

Razor

ASP.NET4

i am using MVC 3 asp.net and Razor, how to validate these drop down boxes ? on client side. Like if no value is selected that pass error to user that please select value.
I have added linq to sql classes which automatically generate things

VIEW:

@using (Html.BeginForm("Generated_PaySlip", "Home", FormMethod.Get))
{
    <fieldset>

            Months 

             @Html.DropDownList("Month", "Select Date")
               
            Employee Name

             @Html.DropDownList("EmplID", "Select Name")
               
             <input type="submit" value="Submit" />

     

    </fieldset>
    
    
}

Controller:

public ActionResult InfoFor_PaySlip() 
        {
            var dates = (from ps in DataContext.MonthlyRecords select new {ps.Month }).Distinct();
            ViewData["Month"] = new SelectList(dates, "Month", "Month");

            var names = (from n in DataContext.HrEmployees select new { n.EmplID, n.EmplName }).Distinct();
            ViewData["EmplID"] = new SelectList(names, "EmplID", "EmplName");
         
            return View();
        }