So im just playing around with my jquery and got stuck with quite odd problem. so i'm getting width of div like this

block_width = $(".grid_block").css("width");

Now i would like to do something with that width let's say

container_width = block_width * 21;

and now if would alert container_width i would get Nah insted of numbers, what am i doing wrong?

So im just playing around with my jquery and got stuck with quite odd problem. so i'm getting width of div like this

block_width = $(".grid_block").css("width");

Now i would like to do something with that width let's say

container_width = block_width * 21;

and now if would alert container_width i would get Nah insted of numbers, what am i doing wrong?

• javascript
• jquery

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9 Answers 9

Sorted by: Reset to default 5

You're getting NaN instead of numbers because the width value you receive will be a string including units

I.E.:

"500px"
"3em"
"27.2%"

You could parse the number with parseInt

width = ...css('width');
width = parseInt(width);

But this is pletely unnecessary because jQuery has the width method.

width = ...width(); //numeric value

.css("width") returns a string representing the width, with "px" appended, i.e. "___px". Multiplying that string with some number fails ("12px" * 2 evaluates to NaN).

You could look into the functions .width() to get the width, and .width(x) to set the width (both as numbers).

Same thing I have done with width()

var block_width = $(".grid_block").width();
var container_width = block_width * 21;
alert(container_width)

Try this Fiddle

You're assigning a string as a part of a math operation...

Try this:

block_width = parseInt($(".grid_block").css("width"));

Your css("width") returns a string, not a number. Convert it using parseInt/parseFloat or use jquery .width() function (which returns number).

You need to use jquery width() method.The difference between .css(width) and .width() is that the latter returns a unit-less pixel value (for example, 400) while the former returns a value with units intact (for example, 400px). Please check http://api.jquery./width/ No need to do parsing for getting the width as other posts suggest.

Remove the px from the end and do a parseInt before your multiplication

block_width = block_width.replace("px", "")
container_width = parseInt(block_width) * 21;

It is because block_width is of int type;

    block_width = intParse($(".grid_block").css("width").replace('px'));
    container_width = block_width * 21

or event better

block_width = $(".grid_block").width();
container_width = block_width * 21

Hy, I came over the same problem. .css("width") returns "20px" for example. What I did, which is sure a bit odd and you could probably solve this with regex but what I did was :

var newWidth = parseInt(($('something').css("width")).split("px")[0])+xx;//xx... Size you want to add
$('something').css("width",newWidth);

I mean you could to everything in one Line also without initializing a new variable but if somebody wants to read your code and is not into jquery or javascript yet, I think its better to split it up. Hope this helps you !