var ck_Name = /^[A-Za-z0-9 ]{3,20}$/;
var ck_Email = /^([\w-]+(?:\.[\w-]+)*)@((?:[\w-]+\.)*\w[\w-]{0,66})\.([a-z]{2,6}(?:\.[a-z]{2})?)$/i;
var ck_Comments = /^[A-Za-z0-9 ]{3,20}$/;


function validate(FormName){
var Name = FormName.Name.value;
var Email = FormName.Email.value;
var Comments = FormName.Comments.value;
  
 var errors = [];
 
 if (!ck_Name.test(Name)) {
  errors[errors.length] = "You must enter a valid Name.";
 }
  
 if (!ck_Email.test(Email)) {
  errors[errors.length] = "You must enter a valid Email Address.";
 }
 
  if (!ck_Comments.test(Comments)) {
  errors[errors.length] = "You must enter a Comment.";
 }

 if (errors.length > 0) {
  reportErrors(errors);
  return false;
 }
 
 return true;
}

function reportErrors(errors){
 var msg = "Please Enter Valid Data...\n";
 for (var i = 0; i<errors.length; i++) {
  var numError = i + 1;
  msg += "\n" + numError + ". " + errors[i];
 }
 alert(msg);
}