问题
Most style guidelines for most programming languages recommend a maximum line length, typically 80 characters. This seems impractically short for HTML and JavaScript (when it is embedded in HTML). Is there a consensus on a practical line length limit for HTML/JavaScript? Or is it generally left up to the developer's common sense?
回答1:
Since you mention JavaScript, this is what Douglas Crockford has to say on the topic:
Avoid lines longer than 80 characters. When a statement will not fit on a single line, it may be necessary to break it. Place the break after an operator, ideally after a comma. A break after an operator decreases the likelihood that a copy-paste error will be masked by semicolon insertion. The next line should be indented 8 spaces.
From: Code Conventions for the JavaScript Programming Language
回答2:
This limit seems to be a legacy from ancient IBM punch cards. Why is 80 characters the 'standard' limit for code width?
I really find it hard to work with only 80 characters for HTML. It gets unreadable really fast. So I decided for myself to take the line length on GitHub as measurement.
There seem to be different character limits depending on OS and/or browser. But 120 should be a quite safe value.
On Ubuntu:
- Firefox: 126
- Opera 12.16: 126
- Chromium: 113
On OSX 10.9:
- Google Chrome: 125
- Firefox: 122
- Safari: 121
Source: What is Github's character limit, or line length for viewing files on github?
On the other hand sometimes choosing your own standard doesn't work. Coding standards or linters for your language or framework might force you to stick to 80 characters. Which at least can be really helpful when it comes to reading code on mobile screens.
But for HTML I'd devo rise this number to 120 characters. For the sake of readability. I mean think of all the CSS-class-heavy frameworks like Bootstrap, what would your template look like in the end with only 80 characters line length? (Apart from that you'd better choose Bourbon Neat which won't pollute your HTML with tons of classes.)
回答3:
Google says 500-ish for JS: https://developers.google.com/closure/compiler/faq#linefeeds
The Closure Compiler intentionally adds line breaks every 500 characters or so. Firewalls and proxies sometimes corrupt or ignore large JavaScript files with very long lines. Adding line breaks every 500 characters prevents this problem.
uglify --max-line-len 500 or grunt-contrib-uglify options: { maxLineLen: 500 }
I'm not sure if the limit applies to HTML or CSS, but I haven't seen that option for any CSS compressor I've used.
SMTP rules would apply to HTML email: https://www.ietf.org/rfc/rfc0821.txt
The maximum total length of a command line including the command word and the CRLF is 512 characters.
回答4:
The 80 character line limit spawns from the days of screens without a lot of real estate. Now it's just like that for readability, and so it's possible to have two (or more) different code files opened side-by-side, without having to scroll to see each of them.
Those reasons still apply to HTML and JavaScript, although, it's obviously not necessary to comply with them. So it's up to you.
I agree that with HTML it can be difficult to keep within that limit, although with JavaScript it shouldn't be a problem.
回答5:
The maximum limit on line length is whatever you feel comfortable reading and editing. personally, any code of mine that won't fit on the screen without wrapping will be rewritten.
回答6:
How about putting all of the HTML on one line? How will browsers cope with that? I've read somewhere that some browser (can't remember which one) breaks with long lines.
Stripping new lines from the file is an optimisation technique. You don't need to give clients the same easy-to-read version that you use when you develop it. You can give them a stripped version. Why? Bandwidth is not free.
回答7:
Many "services" (eg Some terminal window implementations, GitHub, etc) will not wrap long lines and do not have scroll bars.
So anything beyond past 72 or 80 chars can simply get cut off.
Also, it just helps for readability even if there are scrollbars, code can be easier to read/digest/debug if it can fit on (or mostly on) a single screen width.
So while, the code will run, it may not always be able to be displayed in its entirety.
来源：https://stackoverflow.com/questions/2886603/is-there-a-recommended-maximum-line-length-for-html-or-javascript