JavaScript code to stop form submission

JavaScript code to stop form submission

One way to stop form submission is to return false from your JavaScript function.
When the submit button is clicked, a validation function is called. I have a case in form validation. If that condition is met I call a function named returnToPreviousPage();
function returnToPreviousPage() {
window.history.back();
}

I am using JavaScript and Dojo Toolkit.
Rather going back to the previous page, it submits the form. How can I abort this submission and return to the previous page?

Solutions/Answers:

Solution 1:

You can use the return value of the function to prevent the form submission

<form name="myForm" onsubmit="return validateMyForm();"> 

and function like

<script type="text/javascript">
function validateMyForm()
{
  if(check if your conditions are not satisfying)
  { 
    alert("validation failed false");
    returnToPreviousPage();
    return false;
  }

  alert("validations passed");
  return true;
}
</script>

In case of Chrome 27.0.1453.116 m if above code does not work, please set the event handler’s parameter’s returnValue field to false to get it to work.

Thanks Sam for sharing information.

Related:  Angular equivalent of jQuery $.map?

EDIT :

Thanks to Vikram for his workaround for if validateMyForm() returns false:

 <form onsubmit="event.preventDefault(); validateMyForm();">

where validateMyForm() is a function that returns false if validation fails. The key point is to use the name event. We cannot use for e.g. e.preventDefault()

Solution 2:

Use prevent default

Dojo Toolkit

dojo.connect(form, "onsubmit", function(evt) {
    evt.preventDefault();
    window.history.back();
});

jQuery

$('#form').submit(function (evt) {
    evt.preventDefault();
    window.history.back();
});

Vanilla JavaScript

if (element.addEventListener) {
    element.addEventListener("submit", function(evt) {
        evt.preventDefault();
        window.history.back();
    }, true);
}
else {
    element.attachEvent('onsubmit', function(evt){
        evt.preventDefault();
        window.history.back();
    });
}

Solution 3:

The following works as of now (tested in Chrome and Firefox):

<form onsubmit="event.preventDefault(); validateMyForm();">

Where validateMyForm() is a function that returns false if validation fails. The key point is to use the name event. We cannot use for e.g. e.preventDefault().

Solution 4:

Just use a simple button instead of a submit button. And call a JavaScript function to handle form submit:

<input type="button" name="submit" value="submit" onclick="submit_form();"/>

Function within a script tag:

function submit_form() {
    if (conditions) {
        document.forms['myform'].submit();
    }
    else {
        returnToPreviousPage();
    }
}

You can also try window.history.forward(-1);

Solution 5:

All your answers gave something to work with.

Related:  onClick within Chrome Extension not working

FINALLY, this worked for me: (if you dont choose at least one checkbox item, it warns and stays in the same page)

<!DOCTYPE html>
<html>
    <head>
    </head>
    <body>
        <form name="helloForm" action="HelloWorld" method="GET"  onsubmit="valthisform();">
            <br>
            <br><b> MY LIKES </b>
            <br>
            First Name: <input type="text" name="first_name" required>
            <br />
            Last Name: <input type="text" name="last_name"  required />
            <br>
            <input type="radio" name="modifyValues" value="uppercase" required="required">Convert to uppercase <br>
            <input type="radio" name="modifyValues" value="lowercase" required="required">Convert to lowercase <br>
            <input type="radio" name="modifyValues" value="asis"      required="required" checked="checked">Do not convert <br>
            <br>
            <input type="checkbox" name="c1" value="maths"     /> Maths
            <input type="checkbox" name="c1" value="physics"   /> Physics
            <input type="checkbox" name="c1" value="chemistry" /> Chemistry
            <br>

            <button onclick="submit">Submit</button>

            <!-- input type="submit" value="submit" / -->
            <script>
                <!---
                function valthisform() {
                    var checkboxs=document.getElementsByName("c1");
                    var okay=false;
                    for(var i=0,l=checkboxs.length;i<l;i++) {
                        if(checkboxs[i].checked) {
                            okay=true;
                            break;
                        }
                    }
                    if (!okay) { 
                        alert("Please check a checkbox");
                        event.preventDefault();
                    } else {
                    }
                }
                -->
            </script>
        </form>
    </body>
</html>

Solution 6:

Lots of hard ways to do an easy thing:

<form name="foo" onsubmit="return false">