event.preventDefault() function not working in IE

2018-12-31 04:34发布

Following is my JavaScript (mootools) code:

$('orderNowForm').addEvent('submit', function (event) {
    event.preventDefault();
    allFilled = false;
    $$(".required").each(function (inp) {
        if (inp.getValue() != '') {
            allFilled = true;
        }
    });

    if (!allFilled) {
        $$(".errormsg").setStyle('display', '');
        return;
    } else {
        $$('.defaultText').each(function (input) {
            if (input.getValue() == input.getAttribute('title')) {
                input.setAttribute('value', '');
            }
        });
    }

    this.send({
        onSuccess: function () {
            $('page_1_table').setStyle('display', 'none');
            $('page_2_table').setStyle('display', 'none');
            $('page_3_table').setStyle('display', '');
        }
    });
});

In all browsers except IE, this works fine. But in IE, this causes an error. I have IE8 so while using its JavaScript debugger, I found out that the event object does not have a preventDefault method which is causing the error and so the form is getting submitted. The method is supported in case of Firefox (which I found out using Firebug).

Any Help?

11条回答
裙下三千臣
2楼-- · 2018-12-31 05:04

preventDefault is a widespread standard; using an adhoc every time you want to be compliant with old IE versions is cumbersome, better to use a polyfill:

if (typeof Event.prototype.preventDefault === 'undefined') {
    Event.prototype.preventDefault = function (e, callback) {
        this.returnValue = false;
    };
}

This will modify the prototype of the Event and add this function, a great feature of javascript/DOM in general. Now you can use e.preventDefault with no problem.

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弹指情弦暗扣
3楼-- · 2018-12-31 05:06

If you bind the event through mootools' addEvent function your event handler will get a fixed (augmented) event passed as the parameter. It will always contain the preventDefault() method.

Try out this fiddle to see the difference in event binding. http://jsfiddle.net/pFqrY/8/

// preventDefault always works
$("mootoolsbutton").addEvent('click', function(event) {
 alert(typeof(event.preventDefault));
});

// preventDefault missing in IE
<button
  id="htmlbutton"
  onclick="alert(typeof(event.preventDefault));">
  button</button>

For all jQuery users out there you can fix an event when needed. Say that you used HTML onclick=".." and get a IE specific event that lacks preventDefault(), just use this code to get it.

e = $.event.fix(e);

After that e.preventDefault(); works fine.

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萌妹纸的霸气范
4楼-- · 2018-12-31 05:07

I know this is quite an old post but I just spent some time trying to make this work in IE8.

It appears that there are some differences in IE8 versions because solutions posted here and in other threads didn't work for me.

Let's say that we have this code:

$('a').on('click', function(event) {
    event.preventDefault ? event.preventDefault() : event.returnValue = false;
});

In my IE8 preventDefault() method exists because of jQuery, but is not working (probably because of the point below), so this will fail.

Even if I set returnValue property directly to false:

$('a').on('click', function(event) {
    event.returnValue = false;
    event.preventDefault();
});

This also won't work, because I just set some property of jQuery custom event object.

Only solution that works for me is to set property returnValue of global variable event like this:

$('a').on('click', function(event) {
    if (window.event) {
        window.event.returnValue = false;
    }
    event.preventDefault();
});

Just to make it easier for someone who will try to convince IE8 to work. I hope that IE8 will die horribly in painful death soon.

UPDATE:

As sv_in points out, you could use event.originalEvent to get original event object and set returnValue property in the original one. But I haven't tested it in my IE8 yet.

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ら面具成の殇う
5楼-- · 2018-12-31 05:10

FWIW, in case anyone revisits this question later, you might also check what you are handing to your onKeyPress handler function.

I ran into this error when I mistakenly passed onKeyPress(this) instead of onKeyPress(event).

Just something else to check.

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旧时光的记忆
6楼-- · 2018-12-31 05:12

Mootools redefines preventDefault in Event objects. So your code should work fine on every browser. If it doesn't, then there's a problem with ie8 support in mootools.

Did you test your code on ie6 and/or ie7?

The doc says

Every event added with addEvent gets the mootools method automatically, without the need to manually instance it.

but in case it doesn't, you might want to try

new Event(event).preventDefault();
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像晚风撩人
7楼-- · 2018-12-31 05:14

Here's a function I've been testing with jquery 1.3.2 and 09-18-2009's nightly build. Let me know your results with it. Everything executes fine on this end in Safari, FF, Opera on OSX. It is exclusively for fixing a problematic IE8 bug, and may have unintended results:

function ie8SafePreventEvent(e) {
    if (e.preventDefault) {
        e.preventDefault()
    } else {
        e.stop()
    };

    e.returnValue = false;
    e.stopPropagation();
}

Usage:

$('a').click(function (e) {
    // Execute code here
    ie8SafePreventEvent(e);
    return false;
})
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