I'm trying to use this for loop in order to show divs. But I get a strange error from the jQuery lib.

Error: Syntax error, unrecognized expression: =10]

I have read about the problems with javascript decimals, but I still can't understand why this won't work:

for (var i = 10.00; i >= ui.value; i -= 0.25) {
    $("data_id=" + Math.floor(i) + "]").show();
}

When hiding the divs, I use this and it works fine:

for (var i = 0.00; i < ui.value; i += 0.25) {
    $("[data_id=" + Math.floor(i) + "]").hide();
}

I'm trying to use this for loop in order to show divs. But I get a strange error from the jQuery lib.

Error: Syntax error, unrecognized expression: =10]

I have read about the problems with javascript decimals, but I still can't understand why this won't work:

for (var i = 10.00; i >= ui.value; i -= 0.25) {
    $("data_id=" + Math.floor(i) + "]").show();
}

When hiding the divs, I use this and it works fine:

for (var i = 0.00; i < ui.value; i += 0.25) {
    $("[data_id=" + Math.floor(i) + "]").hide();
}

• javascript
• jquery

• 2 Why are you using fractional numbers, if you .floor() them anyways? Try to use an integer loop. – Gregor Commented Sep 16, 2012 at 10:13

4 Answers 4

You forgot the [ in the first loop, this will work:

for (var i = 10.00; i >= ui.value; i -= 0.25) {
    $("[data_id=" + Math.floor(i) + "]").show();
}

You should transform this into an integer loop, if you are .floor()-ing the numbers, anyway.

You're missing your opening square bracket for the attribute equals selector:

for (var i = 10.00; i >= ui.value; i -= 0.25) {
    $("[data_id=" + Math.floor(i) + "]").show();
}

for (var i = 10; i >= ui.value; i--) {
    $("[data_id=" + i + "]").show();
}

This should acplish exactly you want, in about a quarter of the work.

You are missing a [ in your selector here:

$("data_id=" + Math.floor(i) + "]").show();

Which should be:

$("[data_id=" + Math.floor(i) + "]").show();

You should probably add ' around the value of data_id as well, so the final result should be:

$("[data_id='" + Math.floor(i) + "']").show();

You should never, ever rely on floating point arithmetic for iteration/indexing variables. They may run you into strange situations, and even worse, different processors handle floating points differently. Your example doesn't seem to have any side-effects of floating points, but using floating points is really a bad practice.