$("input").blur(function(){
        validate($(this));
      })
      
      $("input").focus(function(){
        
        if($(this).hasClass('invalid')){
          $(this).removeClass('invalid');
          $(this).css({'color':'#666', 'font-size':'15px'});
          $(this).val('');
        }
      })

    });
    
    function removeGuest(val, guest){
      if(confirm("Are you sure you want to remove "+guest+" from the guest list?")){
        $(".guest"+val).remove();
        // re-number remaining guests
        $(".count").each(function(i){$(this).html(i+1)})
      }
    }
    
    function validate(input){
      if(input.hasClass('required')){
        var valid = false;
        var msg = "";
        
        if($(this).hasClass('invalid')){
          $(this).removeClass('invalid');
          $(this).css({'color':'#666', 'font-size':'15px'});
          $(this).val('');
        }
        
        if(input.val()=="" || input.val()=="Please enter a value"){
          valid = false;
          msg = "Please enter a value";
          input.addClass('invalid');
          input.css({'color':'red','font-size':'10px'})
          input.val(msg);
        }
        if(input.attr('id')=="email"  && !Validate_Email_Address(input.val())){
          valid = false;
          msg = "Please enter a valid email address";
          input.addClass('invalid');
          input.css({'color':'red','font-size':'10px'})
          input.val(msg);
        }
        
      }
      
      if(valid){
       return true
      }
      else {
        return false
      }
    }
    
    function validateForm(){
      // clear old errors
      $(".invalid").val('');
      
      var valid = true;
      $.each($("input.required"), function(){
          var input = $(this);
          var msg = "";
          
          if(input.val()=="" || input.val()=="Please enter a value"){
            valid = false;
            msg = "Please enter a value";
            input.addClass('invalid');
            input.css({'color':'red','font-size':'10px'})
            input.val(msg);
          }
          
      })
      
      return valid;
      
    }
    
    function Validate_Email_Address(email_address)
             {
             //Assumes that valid email addresses consist of user_name@domain.tld
             at = email_address.indexOf('@');
             dot = email_address.lastIndexOf('.');

             if(at == -1 || 
                dot == -1 || 
                dot <= at + 1 ||
                dot == 0 || 
                dot == email_address.length - 1)
                return(false);

             user_name = email_address.substr(0, at);
             domain_name = email_address.substr(at + 1, email_address.length);                  

             if(user_name === false || 
                domain_name === false)
                return(false);                     

             return(true);
             }