How to add pixels to an existing value of pixels in JavaScript?

[bendqh1]

I need to add 25px to an iframe with somewhat dynamic height, to compensate for 25px of padding that this iframe already got (and by doing so ridding end-users from the need to scroll-down these extra 25px).

I tried this:

iframeToWorkOn.height += "25px";

It added about 47525px instead just 25px and I have no clue why.

[DaveMaxwell]

You don’t need to set it by pixels - that should be the default dimension (I think)

iframeToWorkOn.height += 25;

[bendqh1]

@DaveMaxwell

iframeToWorkOn.height += 25;

I still get about 47525px instead just 25, this way…

[Gandalf]

I think it is probably concatenating the 25 onto the current frame height. You need to ensure it is performing an arithmetic addition.

What is the value of iframeToWorkOn.height?

[bendqh1]

@bendqh1

iframeToWorkOn.height

From executing iframeToWorkOn.height in browser console its value is 300 (px).

[DaveMaxwell]

Ahhh…should have looked closer and caught this - height returns a string.

So you’ll need to do something like this.

iframeToWorkOn.height = (parseInt(iframeToWorkOn.height) + 25);

[bendqh1]

Thanks, I think it works.

Just one question why is the parseInt() method and the + 25 arithmetic operation where both wrapped in parenthesis?

[DaveMaxwell]

You don’t need the wrapping parenthesis. I did it for readability but this works as well.

iframeToWorkOn.height = parseInt(iframeToWorkOn.height) + 25;