Do spaces/comments slow Javascript down?

I was wondering, do whit开发者_StackOverflow社区espaces and comments slow down JavaScript? I'm doing a brute force attack which takes some time (30 seconds). Removing whitespaces does not show a significant growth in speed, but I think the browser just does have to parse more.

So, is it of any use to remove unnecessary whitespaces and comments to speed the whole up?

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People usually use minimizers to reduce the SIZE of the script, to improve download speed, rather than to make any difference in speed of parsing the script.

Whitespace and comments will have little effect in how long it takes a browser to execute, as the parser needs to check if it is whitespace, or a comment, but in reality this will be so minute with current computing power, it would be impossible to notice any impact.

SIZE however is still important even with the large bandwidth available in our broadband world.

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Whitespaces and comments increase the size of the JavaScript file, which slows down the actual downloading of the file from the server - minification is the process of stripping unnecessary characters from a JavaScript file to make it smaller and easier to download.

However, since you mention a brute force attack, the bottleneck is probably not the download. Try using a profiler to find what slows you down.

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There is always a point in minifying, combining and gzipping your assets, to ease server load.

• Minifying is the act you refer to, of stripping away unnecessary whitespace and comments, to make the download speed smaller.
• Combining will most likely show an even greater increase in page rendering speed; it is the act of merging all your javascript files into one, and all your css files into one (it can also be done for most images, but that taks requires some more work). This is done to reduce the amount of requests the browser has to make towards your server, to be able to display the page.
• GZipping is the act of further compressing the data, in a zipped format, to the browsers that indicate that they'll accept such data. This further reduces size, but adds some extra work load at both ends. You're likely to see a net gain from it.

Depending on what environment you're working in, there are different components that'll help you with this, that usually covers all of the above in one go.

The time your code takes to download from the server has a direct effect on how long the page takes to render. JavaScript is blocking, meaning that a JS block will prevent any furhter rendering, until the block has executed entirely. As such, where you put your javascript files (i.e. in which point in the rendering process they'll be requested), how many requests it takes for it to be completely downloaded, and how much data there is to download, will have an impact on your page load, as it appears to the user.

Once the browser has parsed your code, be it javascript, css or html, it'll have created internal representations of the part it needs to keep remembering, and the actual formatting will no longer affect it.

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I don't think whitespace in js-code slows down the execution of it. As far as I understand a javascript interpreter strips all comments and redundant whitespace before processing. It can influence download time en thus loading time of a web page however.

Take a look here for a bit of extra information.

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It has little to no impact on actual processing speed, however...

Smaller size => less bandwith => less costs => ??? => profit!