Javascript IE error: 'target' is null or not an object

Question

document.onkeydown = function(event) {
    var tagName = event.target.tagName;
    if (tagName != 'INPUT' && tagName != 'TEXTAREA' && !event.alt && event.control) {

        if (event.ctrlKey && event.keyCode == 37) {
            if (_this.currentPage > 1) {
                window.location.href = _this.baseUrl.replace(/%page%/i, _this.currentPage + 1);
            }
        } else if (event.ctrlKey && event.keyCode == 39) {
            if (_this.currentPage < _this.pagesTotal) {
                window.location.href = _this.baseUrl.replace(/%page%/i, _this.currentPage - 1);
            }
        }
    }
}

This gives me an error only in IE 8:

'target' is null or not an object

for that line var tagName = event.target.tagName;

How to fix that? Error happens when I press Ctrl or arrows button.

event.target does not exist in IE8. Welcome to IE's old event system. — Šime Vidas
– Šime Vidas, Commented Nov 12, 2012 at 2:06
Use a third-party event API what takes care of the cross-browser incompatibilities for you. That would be my advice. — Šime Vidas
– Šime Vidas, Commented Nov 12, 2012 at 2:11
Yeah, but I am not good at all in Javascript. I need example what to change. — user1815131
– user1815131, Commented Nov 12, 2012 at 2:13

Joseph Silber · Accepted Answer · 2012-11-12 02:10:25Z

6

IE does not pass in the event object into the event handler. Instead, they use the global event property of the window object. So for IE, you'd use window.event instead.

It is common practice to test for the supplied argument first. You also have to take into account the fact the IE uses srcElement instead of target. To account for all that, use something similar to this:

document.onkeydown = function(event) {
    event = event || window.event;
    var tagName = (event.target || event.srcElement).tagName;
    // Keep up the good work...
}

This should do the trick.

edited Nov 12, 2012 at 2:10

answered Nov 12, 2012 at 2:04

Joseph Silber

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5 Comments

I Hate Lazy Over a year ago

For a second there it looked like a direct copy/paste. Why remove the toUpperCase?

user1815131 Over a year ago

You know I tried that before. It didn't help me. Then it gives the same error on the next line var tagName = event.target.tagName;.

Joseph Silber Over a year ago

@user1689607 - I just don't think people should still be using quirks mode. I definitely hope the OP is using a proper doctype. AFAIK, when in standards mode, IE will return the element's name in uppercase. Someone correct me if I'm wrong.

I Hate Lazy Over a year ago

There are a couple edge cases for IE (I don't remember which versions).

user1815131 Over a year ago

Thank you! The additional answer below fix the problem.

Joseph Silber · Accepted Answer · 2012-11-12 02:15:33Z

3

Do it like this:

event = event || window.event;
var tagName = (event.target || event.srcElement).tagName.toUpperCase();

edited Nov 12, 2012 at 2:15

Joseph Silber

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answered Nov 12, 2012 at 2:07

I Hate Lazy

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1 Comment

user1815131 Over a year ago

The same then it gives the same error on the next line var tagName = event.target.tagName.toUpperCase();.

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