var errorEncountered = false; 
  var errorEncountered2 = false;
  
  function validateContactForm()
  {
      
      var formID="form_contactus";
      var form = document.getElementById(formID);
      
      form.onsubmit = function()
      {
          
          var inputName = document.getElementById("Name");
          var inputNameValue = inputName.value;
          
          var inputEmail = document.getElementById("Email");
          var inputEmailValue = inputEmail.value;
          
          if(TrimString(inputNameValue)=="")
          {

                  var ni = document.getElementById('name_req');
                  ni.className = "error";
                  
                  ni.innerHTML = "please enter your name";
                  
                  errorEncountered = true;
          
          }
          else
          {
              if(errorEncountered == true)
              {
                  
                  var ni = document.getElementById('name_req');
                  ni.className = "";
                  
                  ni.innerHTML = "";
              }
              errorEncountered = false;
          }
          
          if(TrimString(inputEmailValue)=="")
          {
             
                  var ni = document.getElementById('email_req');
                  ni.className = "error";
                  
                  ni.innerHTML = "please enter you email address";
                  
                  errorEncountered2 = true;
      
          }
          else if(inputEmailValue.indexOf('@') == -1 || inputEmailValue.indexOf('.')== -1)
          {
             
              var ni = document.getElementById('email_req');
              ni.className = "error";
              
              ni.innerHTML = "not a valid email address";
              
              errorEncountered2 = true;
          }
          else if(inputEmailValue.lastIndexOf('@') >= inputEmailValue.lastIndexOf('.'))
          {
               var ni = document.getElementById('email_req');
              ni.className = "error";
              
              ni.innerHTML = "not a valid email address";
              
              errorEncountered2 = true;
          }
          else
          {
              if(errorEncountered2 == true)
              {
                  
                  var ni = document.getElementById('email_req');
                  ni.className = "";
                  
                  ni.innerHTML = "";
              }
              errorEncountered2 = false;
          }
          
          if(errorEncountered || errorEncountered2)
          {
              return false;   
          }
         
          
      }
  }
    
    function TrimString(sInString) {
      sInString = sInString.replace( /^\s+/g, "" );// strip leading
      return sInString.replace( /\s+$/g, "" );// strip trailing
    }

    function addLoadEvent(func) 
    {
        var oldonload = window.onload;
        if (typeof window.onload != 'function') {
            window.onload = func;
        }
        else {
            window.onload = function() {
                oldonload();
                func();
            }
        }
    }

    addLoadEvent(validateContactForm);