WTF Javascript?

function map(proc, lst) {
    var res = [];
    for (var obj in lst)
        res.push(proc(obj));
    return res;
}

function filter(pred, lst) {
    var res = [];
    for (var obj in lst)
        if (pred(obj))
            res.push(obj);
    return res;
}

ls = [1, 2, 3, 4, 5, 6, 7, 8, 9, 10];

ls = map(function(x) {
    return x * x;
}, ls);

print(ls);

ls = filter(function (x) {
    return x % 2 == 0;
}, ls);

print(ls);

What I expect:
0,1,4,9,16,25,36,49,64,81
0,4,16,36,64

What I get:
0,1,4,9,16,25,36,49,64,81
1,3,5,7,9

WHY?

Never mind, I figured it out. for (var x in y) considered harmful, unscientific and ultimately destructive.

so obj was just the index of the slot in the array or what?

>>3
Yeah. Furthermore, if you were to use it on a DOM structure, I would give you an index for each leaf in the tree. It's almost never safe to use.

>>4
javascript has so many strange caveats. I guess it's ok once you have enough knowledge to avoid them, but for a newcomer you can get hung up on this type of stuff for a while. Javascript got me so hard with the forced stringification of keys. I can't remember what the exact usage was though.

>>5
Watch Crockford on Javascript, should only take 8 hours or so. If you don't have time just watch the "Function the Ultimate" one.

you should never expect javascript to do what you want. it was designed for pop-up ads and nothing else

>>6
SUGOI

want to fill in the form on http://www.unblockyoutube.us/

normally i'd do document.FORMNAME.FIELDNAME.value='TEXT GOES HERE';

But the form on that page has no name or fields (I tried "url_form and "a" respectively without success).

Now, I also tried document.getElementsByTagName('form')[0].value='TEXT';

But that didnt work either.

Any pointers?

document.getElementsByClassName("form")[0].value = "pepe"

gives you a blank page with text

JavaScript is broken by design.

It's time to code apps and check dubs, and I'm not all out of dubs.

>>9
document.getElementsByTagName('input')


    for (var obj in lst)
        if (pred(lst[obj]))
            res.push(lst[obj]);

FTFY. JS (maddeningly) assigns the index in for loops, not the value. (You'll need to fix map too, 1 * 1 is not 0.)

Also, WTF are you not using Array.map and Array.filter?