CODEWITHSUNDEEP
javascripthtmltext-formatting
user723636
user723636

Reputation: 189

Why doesn’t JavaScript newlines work inside HTML?

I have the following:

<html>
  <body>
    <script type="text/javascript">
      document.write('Hello\nWorld')
    </script>
  </body>
</html>

As you probably all know, \n doesn’t work and I have to use <br> instead. It won’t work either if I link to an external .js file. Here are my questions:

  1. Why doesn’t \n work?
  2. Why does <br> even work? Shouldn’t everything that’s inside the script tags be strictly JavaScript instead of a dirty mix between HTML and JS?
  3. Is it possible to make \n work somehow?
  4. I know \t doesn’t work either. Any other stuff that won’t work inside HTML files?
  5. Unrelated question (I didn’t want to open a new question just for this): I installed Node.js to be able to try out JS scripts from inside vim but when I run this script I get the error "document is not defined". Same thing happens when I try from the REPL. Any ideas?

When searching for similar questions, all I got was that I should use <br> instead of \n.

Upvotes: 17

Views: 59534

Answers (13)

Quentin
Quentin

Reputation: 943108

Why doesn’t \n work?

Because white space is just white space in HTML.

Why does <br> even work?

Because it is the HTML for a line break

Shouldn’t everything that’s inside the script tags be strictly JavaScript instead of a dirty mix between HTML and JS?

That’s subjective. document.write is considered dirty by many as well.

You can always use createElement and createTextNode

Is it possible to make \n work somehow?

<pre>, white-space

I know \t doesn’t work either. Any other stuff that won’t work inside HTML files?

HTML is not plain text. Listing all the differences would be time-consuming, and out of scope for Stack Overflow. Try reading the specification.

Unrelated question (I didn’t want to open a new question just for this)

It is completely unrelated. Open a new question.

Upvotes: 22

davin
davin

Reputation: 45525

\n works. If you have a debugger of sorts (or similar developer tool), you can see the document source, and you will see that there is indeed a newline character. The problem is the way you are looking at the page: you’re not reading its source, you’re reading it as an HTML document. Whitespace in HTML is collapsed into a single space. So when you change the source, it does indeed change, although when interpreted as an HTML document, that change isn’t shown.

Your Node.js error is most probably caused by the fact that you’re running browser scripts on the server. I.e. scripts that refer to the document are intended to be run in a browser, where there is a DOM etc. Although a generic node process doesn’t have such a global object because it isn’t a browser. As such, when you try and run code that references a global object called document on the assumption that it exists just like in the browser, it will throw an error. document.write doesn’t exist; if you want to write to the screen, try console.log or look into the other util functions.

Upvotes: 9

Mahdieh Shavandi
Mahdieh Shavandi

Reputation: 8645

I had:

<div>Hello\nworld</div>

I added the below css to div class and it's working now:

div {
      white-space: pre-wrap;
  }

I hope this solve your problem too.

Upvotes: 38

NATHAN SILVA SANTOS
NATHAN SILVA SANTOS

Reputation: 49

Use <pre></pre> on the html and it will respect the text format from JS.

Upvotes: 3

neeebzz
neeebzz

Reputation: 11538

Everyone has said what it was to be said but in case if you are using firebug/chrome Javascript console ..then try this >

console.log("Hello\nWorld");

This is the key difference. When you are printing something in HTML, the HTML rules apply. Elsewhere you can see the line breaks work.

Upvotes: -2

Aryo Sanjaya
Aryo Sanjaya

Reputation: 27

Actually your code is works. When you run it on browser console like Firefox, it will show you:

<html><head></head><body>
    <script type="text/javascript">
      document.write('Hello\nWorld')
    </script>Hello
World

</body></html>

Note on the Hello and World that is separated.

But when displayed on HTML, line break (whitespace) will be ommited.

To display "as is", you may surround the javascript with PRE tag, like:

<html>
  <body>
    <pre>
    <script type="text/javascript">
      document.write('Hello\nWorld')
    </script>
    </pre>
  </body>
</html>

You will get your line break displayed on HTML.

Upvotes: -2

Mark Cidade
Mark Cidade

Reputation: 99957

The document object represents an HTML document; any text written to the document will be processed by the browser's HTML renderer. In HTML, all adjacent whitespace, including line breaks (e.g., "\n"), are collapsed into a single space when rendered. This is why you need <br />, which is rendered as a line break. You can make \n work by replacing it with <br /> or by writing into a <pre> element:

Hello
World

Upvotes: -1

Adam Bergmark
Adam Bergmark

Reputation: 7536

1,3. "\n" does work. If you do a document.write inside the body tag you can check document.body.innerHTML and see that the line break is indeed there.

4.Anything HTML specific will be rendered HTML specific, so you will have to escape < and > into &lt; and &gt; for instance.

5.document is an object available in browsers, it is not used in node since the DOM doesn't exist there. require("sys"); and use sys.print in nodejs.

Upvotes: -1

Spliffster
Spliffster

Reputation: 7209

Use the html tag <br/> to input line endings (your output is interpreted by an html parser), for example:

Javascript:

document.write("Hello<br/>World");

Upvotes: 2

mattsven
mattsven

Reputation: 23253

1) \n works in plain text files.

2) <br /> works because you are doing HTML in string. Strings can hold characters without breaking the rest of the JS script.

3) Not really. Perhaps when you are using <textarea>s.

4) Most other \*'s

5) More info needed.

Upvotes: -1

Chris Kooken
Chris Kooken

Reputation: 33880

When HTML renders, it ignores whitespace. Thus the only way is to use line breaks.

Use <br/> instead of \n and it will work fine

The document.write() function writes HTML into the element.

Upvotes: 3

Jonathan Wood
Jonathan Wood

Reputation: 67175

Whitespace emitted by JavaScript works like any other whitespace in your HTML file. That seems the expected behavior to me.

Upvotes: -1

BraedenP
BraedenP

Reputation: 7215

When you write to the page, you're not writing JavaScript; you're writing HTML. \n is a special "line feed" character that doesn't create a line break in the browser's rendering of the HTML. It WILL create a line break in the HTML file itself, but the browser doesn't take this into consideration when it renders out the markup.

Thus, the br tag is required.

Upvotes: 2

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