javascript - 如何添加一个错误而不是多个错误

Question

嗨，我已经设计了我的表单，现在我不确定如何组合所有警报消息，而不是一次弹出一个警报消息，请有人告诉我如何简单地做到这一点，因为我是 JavaScript 新手。先感谢您。下面是我的脚本。

function validateForm() {
// this part of the script will collate all errors into one should the user leave an input blank
var Fname=document.forms["myForm"]["fname"].value;
var Lname=document.forms["myForm"]["lname"].value;
var address=document.forms["myForm"]["addr1"].value;
var postcode=document.forms["myForm"]["pcode"].value;
var email=document.forms["myForm"]["email"].value;
var number=document.forms["myForm"]["tel"].value;
var date=document.forms["myForm"]["mydate"].value;
if (Fname==null || Fname=="" ||Lname==null || Lname=="" ||address==null || address=="" ||!postcode||!email||!number||( myForm.sex[0].checked == false ) && ( myForm.sex[1].checked == false )||(myForm.age[0].checked == false )&&(myForm.age[1].checked == false )&&(myForm.age[2].checked == false )&&(myForm.age[3].checked == false )&&(myForm.age[4].checked == false )||!date)
  {
  alert("Please make sure all fields are filled or checked correctly out ");
  return false;
  } 
  //end of collating script
  //start of postcode script
 var regPostcode = /^[a-zA-Z]{1,2}\d[\dA-Za-z]? \d[a-zA-Z]{2}$/;
if (!postcode.match(regPostcode))
{
    alert("That Post Code is incorrect, correct way mk4 4tr");
    return false;
}
//end of postcode script
//start of email script
var regEmail =/^\S+@\S+\.\S+$/;

if (!email.match(regEmail))
{
    alert("That email is incorrect");
    return false;
}


// end of email script
// start of phone number script
 var phonestring = /^(?:0|\+44)[12378]\d{8,9}$/;
if (!number.match(phonestring))
{
    alert(" incorrect,correct format 01908234874");
    return false;
}
// end of phone script
//start of gender script

if ( ( myForm.sex[0].checked == false ) && ( myForm.sex[1].checked == false ) ) 
{
alert ( "Please choose your Gender: Male or Female" ); 
return false;
}
// end of gender script
//start of age group script
if((myForm.age[0].checked == false )&&(myForm.age[1].checked == false )&&(myForm.age[2].checked == false )&&(myForm.age[3].checked == false )&&(myForm.age[4].checked == false )){
alert("please select an age group");
return false;
}
// end of age script
//start of datefield
var dateformat=/^(?:(?:31\/(?:0[13578]|1[02])|(?:29|30)\/(?:0[13-9]|1[012])|(?:0[1-9]|1\d|2[0-8])\/(?:0[1-9]|1[0-2]))\/[2-9]\d{3}|29\/02\/(?:[2-9]\d(?:0[48]|[2468][048]|[13579][26])|(?:[2468][048]|[3579][26])00))$/;
if (!date.match(dateformat))
{
    alert("format incorrect use dd/mm/yyyy make sure you are entering correct days to the month remember 30 days have september, april, june & november, only 28 days in february unless leap year next is 2016");
    return false;
}
var today = new Date();

var courseYear =date.substr(6,4) // use substr or substring to capture the last four digits
var courseMonth =date.substr(3,2) // use substr or substring to capture the four and fifth digits
var courseDay = date.substr(0,2)//e the first and second digits

var dateToCompare = new Date(courseYear, courseMonth, courseDay);

if (dateToCompare < today) {
alert("this date is in the past"); 
return false; }

//end of date field
else
{ alert(" Thank you a member of our team will get back to you shortly");

return true;}
}

Answer 1

创建某种可以附加到的集合，而不是独立地发出警报，只需将它们添加到集合中即可。像这样的东西:

function validateForm(){
  var errors = []; // new array to hold all the errors

  /*
    validation code that instead of
      alert('error')
    use
      errors.push('error');
    Also remove any premature `return` statements and
    leave them until the end.
  */

  // next check if there are errors
  if (errors.length > 0){
    // display them
    alert('Following errors found:\n- ' + errors.join('\n- '));

    // also return false to flag there was a problem
    return false;
  }

  // if we reached this code there were no errors
  return true;
}