Javascript can't create dictionary in IE - javascript

var Dictionary = {
foo: "bar"
}
alert(Dictionary.foo)
This works fine in Firefox 6, but not in IE8, is there a syntax error that FF is displacing, or do I need an IE fix?

This example does work in IE8 - at least for me. I'm running on a Windows XP SP 3 with the latest IE8.
If you have problems with some Object-notations, check if your key is named like keywords which are specified in JavaScript, like class and aren't defined as a String (you need to write it as "class". Otherwise missing colons are often a source of errors.

Related

Does this kind of value setting work in Javascript?

I'm trying to create code that requires the least number of bytes and that works for all browsers including IE 7.
In this example, the program calls dosomething('x1') and dosomething('x2').
If I have code like this:
var items,item,index,count;
items=Array('x1','x2');
count=items.length;
for (index=0;index<count;index++){
item=items[index];
dosomething(item);
}
Could I reduce it to this and have it still function exactly the same in all browsers:
var a=Array('x1','x2'),c=a.length,i;
for (i=0;i<c;i++){
f(a[i]);
}
I understand I changed the variable names and calling function name but my goal is to use the least number of bytes possible in the code to make the code execute.
I'm just not sure if declaring a variable equal to a property of a value from a previous variable in the same list of declarations would actually return correct results.
In other words, does var a=Array('x1','x2'),c=a.length... work, or do I have to specifically do var a=Array('x1','x2');var c=a.length; to make it work in all browsers including IE 7?
This is what the Google Closure Compiler service returned:
var a,b,c,d;a=["x1","x2"];d=a.length;for(c=0​;c<d;c++)b=a[c],dosomething(b);
You can find many different Javascript compressors online to automate the process you are hand coding now. Yet, it's always good to understand how they work as it helps to write code that is better compressed.
As for IE, you can test your code by changing the emulations settings in the IE debugger panel. Just press F12, click the Emulation tab, and adjust the document mode to 7 (IE7).
Hope this is enough to get you started in the right direction.
You can use Array.map from IE 9
var items = Array('x1','x2');
items.map(dosomething(item));

IE7 converting bracket notation to . notation in javascript

I have this line of code (where 'e' is a click event):
var type = $(e.currentTarget.parentNode)[0].classList[0];
which is producing this error in IE7 (using Companion.JS to report errors):
'0.classList.0' is null or not an object
I tried the following variations on my code, but get the same result:
var type = $(e.currentTarget).parent()[0].classList[0];
var type = $(e.currentTarget).parent()['0'].classList['0'];
This code works in the latest Chrome and Firefox browsers. Any idea what's going on here?
First check the .length of $(e.currentTarget.parentNode), you might have to add a condition for IE because the currentTarget is inconsistent with other browsers.
Also, classList is not supported in IE.
Code with classList does not work in IE?
parse the .attr('class') or [0].className

Jquery issues on older versions of IE

I have the following statement in document.ready function:
if($("sidebar ").html().trim().length == 0)
{
$("sidebar").append("<p> The sides..</p>");
};
It works fine in IE 9 but as soon as I select IE 8 (browser and document standard), the script stops working and gives the following error:
SCRIPT5007: Unable to get value of the property 'trim': object is null or undefined
application-e51c9eee7d22e9644481115dc1fedd5f.js, line 7 character 17578
I looked at the .js in debug mode and see that my statement above is transformed to:
$("sidebar ").html().trim().length==0&&$("sidebar").append("<p> The sides..</p>")
How do I prevent this error? Please note that I do see that the node is present in the rendered page.
I thought that maybe just having reference to shiv5.html may not be sufficient to take care of the IE idiosyncrasies. So, I have added modernizr.js via sprockets and I have added class="no-js" in my layout. Still no luck in IE <9.
What am I missing? What else can I do to get the favor of Microsoft overlords?
According to MDN, trim isn't available in IE < 9.
You could use $.trim instead:
if($.trim($("sidebar ").html()).length == 0)
{
$("sidebar").append("<p> The sides..</p>");
} // <-- Don't want a semicolon here.
The MDN article lists an alternative if you don't want to find all the instances of trim and correct them. You could use the following to create .trim if it's not natively available:
if(!String.prototype.trim) {
String.prototype.trim = function () {
return this.replace(/^\s+|\s+$/g,'');
};
}
Check out this thread. After a quick search it seems that many people are experiencing issues with trim.

Why does Internet Explorer not like this jQuery?

While debugging some jQuery that is not working in IE, I found this error message:
var item = $("#item_"+ itemArray[itemIndex]).find('a').text().trim();
Object doesn't support this property or method (script.js, line 100, character 2)
The character 2 doesn't make sense to me. Based on the text displayed character 2 would be the letter a in var but of course that doesn't make any sense.
(Should I not use var?)
I know that jQuery is working to some extent or the script would not have been able to get this far on my page.
IE doesn't have String.trim(), you'll need $.trim() (which uses native trim if available, emulates it in IE), like this:
var item = $.trim($("#item_"+ itemArray[itemIndex]).find('a').text());
IE doesn't have a trim method.
Instead, you can call jQuery.trim(...).

A weird regex problem

The following code results in "undefined" for lastIndex:
var a = /cat/g;
var l = "A test sentence containing cat and dog.";
var r = a.exec(l);
document.write(r.lastIndex);
However, it works perfectly for r.index (and r.input).
I am using Firefox. Does anybody have a clue?
EDIT: OK, the above code works perfectly in IE! Further, in Firefox, it works perfectly if instead of calling r.lastIndex on line 5, a.lastIndex is called. It appears that Firefox does not return lastIndex property in the result - rather sets the property for the pattern invoking the exec() only. Interesting that IE sets both.
This is one of those places where Microsoft decided to add some stuff to the language and act as if it was supposed to be there. Thankfully, they are now cleaning up their act and documenting such nonsense.
To be clear: Firefox is correct according to the ECMAScript Language Specification 3rd Edition (PDF, 705KB).
IE is not correct; its behaviour is a proprietary extension. There is no reason to believe that this IE-specific behaviour will ever be supported by any other browser. It certainly isn't at the moment. See JScript Deviations from ES3 (PDF, 580KB, by Pratap Lakshman of Microsoft Corporation) Section 4.6 for more on this particular deviation from the spec, including tests showing no support on other browsers.
Note also that this may not even be supported in the future by IE: a number of proprietary IE CSS-related mechanisms are disabled by default on IE8-in-IE8-mode, and future implementations of JScript may find a reason to similarly disable this extension to the language.
lastIndex is a property of a RegExp object. So try this:
a.lastIndex
To avoid all the weird, try this
var a = /cat/g;
var l = "A test sentence containing cat and dog.";
var r = a.exec(l);
var lastIndex = (r!=null) ? l.indexOf(r[0])+r[0].length : 0;
It is used here: http://www.pagecolumn.com/tool/regtest.htm

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