即使侦听器函数返回 false，表单仍会提交

Question

I'm trying to figure out why this JavaScript doesn't stop the form from being submitted:

<form action="http://www.example.com" id="form">
    <input type="text" />
    <input type="submit" />
</form>

<script>
var code = function () {
    return false;
};
var element = window.document.getElementById("form");
if (element.addEventListener) {
    element.addEventListener("submit", code, false);
}
</script>

Unless I add the following onsubmit attribute to the form element:

<form action="http://www.example.com" id="form" onsubmit="return false">
    <input type="text" />
    <input type="submit" />
</form>

<script>
var code = function () {
    return false;
};
var element = window.document.getElementById("form");
if (element.addEventListener) {
    element.addEventListener("submit", code, false);
}
</script>

Seems like the addEventListener method alone should do the trick. Any thoughts? I'm on a Mac and I'm experiencing the same result on Safari, Firefox and Opera. Thanks.

Answer 1

Combined the information from the two very helpful answers into a solution that works on both Mac and PC:

<script>
var code = function (eventObject) {
    if (eventObject.preventDefault) {
        eventObject.preventDefault();
    } else if (window.event) /* for ie */ {
        window.event.returnValue = false;
    }
    return true;
};
var element = window.document.getElementById("form");
if (element.addEventListener) {
    element.addEventListener("submit", code, false);
} else if (element.attachEvent) {
    element.attachEvent("onsubmit", code);
}
</script>

Answer 2

Looks like if you change your function to

var code = function(e) {
    e.preventDefault();
}

It should do what you're looking for.

source

Answer 3

I think what you're looking for is the preventDefault() method of the Event interface for browsers that implement it. It will cancel the form submission in the way you expected " return false " to.

More here and here .

<script type="text/javascript">
 var code = function (evt) {
            if (evt.preventDefault) {
                evt.preventDefault();
            }
            return false;
};
window.onload = function() {
    var element = window.document.getElementById("form");
    if (element.addEventListener) {
        element.addEventListener("submit", code, false);
    }
};
</script>