Input girişine Java Script Ekleme ?

<input type="text" name="tckimlikkk1" size="16" style="font-family: Tahoma; " maxlength="11">

public Boolean TcKimlikKontrol(String kimlikNo) 
{ 
Tc = kimlikNo; 
int no = 0; 
no = no + Convert.ToInt32(Tc.Substring(0, 1)); 
no = no + Convert.ToInt32(Tc.Substring(1, 1)); 
no = no + Convert.ToInt32(Tc.Substring(2, 1)); 
no = no + Convert.ToInt32(Tc.Substring(3, 1)); 
no = no + Convert.ToInt32(Tc.Substring(4, 1)); 
no = no + Convert.ToInt32(Tc.Substring(5, 1)); 
no = no + Convert.ToInt32(Tc.Substring(6, 1)); 
no = no + Convert.ToInt32(Tc.Substring(7, 1)); 
no = no + Convert.ToInt32(Tc.Substring(8, 1)); 
no = no + Convert.ToInt32(Tc.Substring(9, 1)); 
string son = Convert.ToString(no).Substring(1, 1); 
if (son == Tc.Substring(10, 1)) 
{ 
return true; 
} 
else 
{ 
return false; 
} 
}

function IsNumeric(sText)

{
   var ValidChars = "0123456789.";
   var IsNumber=true;
   var Char;

 
   for (i = 0; i < sText.length && IsNumber == true; i++) 
      { 
      Char = sText.charAt(i); 
      if (ValidChars.indexOf(Char) == -1) 
         {
         IsNumber = false;
         }
      }
   return IsNumber;
   
   }