Form onSubmit function not firing when form submitted

Question

I have had a look and cannot find anything like my problem.

I have a form where I cannot get the validation to work. I know the JavaScript file is loading since other functions on the page are working without issue. My code is as follows:

  <form method="post" name="selectMod" action="check.php" onsubmit="validate()">

There is then the form and the button is coded as follows:

  <div class="form-row">
                <div class="col-sm-12 col-md-12">
                    <button type="submit" class="btn btn-success btn-block center-block">Submit</button>

At the moment the code in the function is set to just return false since I cannot get it to work.

  function validate(){
  return false;
  }

Sure I am missing something obvious but cannot see what it is.

Answer 1

It is firing. It just doesn't do anything with observable effects.

1. The onsubmit function calls validate
2. The validate function returns false (because it has a return statement)
3. The onsubmit function ignores that return value
4. The onsubmit function returns undefined (because it doesn't have a return statement

If you want to prevent the default behaviour of the submit event, then you need to return false from the onsubmit function

onsubmit="return validate()"

---

Modern code would avoid intrinsic event attributes in favour of binding event listers with JavaScript and manipulating the event object.

var myForm = document.querySelector("form");
myForm.addEventListener("submit", validate);
function validate(event) {
    event.preventDefault();
}

Answer 2

You can use following:

 function validate(){
    //if check false
    event.preventDefault();
    return false;
 }

Answer 3

在 check() 函数中， getEforlementById语法无效