document.write with CoffeeScript

Question

document.write with CoffeeScript

3.1k Views Asked by zanona At 16 May 2025 at 23:24

I know I am probably doing this wrong because if trying this through try coffeescript feature it works but surprisingly it doesn't emit any result on my example:

<!--http://f.cl.ly/items/1u3Q3W101U2T18162v0V/test.html-->
<!DOCTYPE html>
<html>
<head>
  <meta charset="utf-8">
  <title>Page Title</title>
  <script src="http://jashkenas.github.com/coffee-script/extras/coffee-script.js"></script>
</head>
<body>
  <script type="text/coffeescript" >
    document.write "<h2>TEST</h2>"
  </script>
</body>
</html>

The document.write method doesn't seems to output anything to the body, in this case console.log works fine but not document.write

Even after trying to run the script with a onload handler like I use in javascript

var loaded = function(){
  alert("hello");
}

document.addEventListener('DOMContentLoaded', loaded);

but then in coffeescript as

loaded = ->
   alert "hello"

document.addEventListener "DOMContentLoaded", loaded

it seems neither the event method is being fired as opposed to javascript version

Anyone could help me find out what is happening?

Thanks

UPDATE

if running the console after the page is loaded I can get the following to work without problem:

CoffeeScript.eval('document.write "<h1>testing</h1>"')

but still wondering why the page itself is not showing automatically

Works on Firefox and Chrome but not in Safari

It seems the page is not showing if using Safari 5.0.3

Original Q&A

There are 2 best solutions below

Erlend On 22 February 2011 at 15:31

I don't know anything about CoffeeScript, but don't use document.write. It is evil: http://javascript.crockford.com/script.html

Use createElement and appendChild/insertBefore instead:

var p = document.createElement("p");
p.innerHTML = "Lolz";
document.body.appendChild(p);

myDiv = document.getElementById("aDiv");
document.body.insertBefore(p, myDiv);

document.write has problems in Safari as well.

**Trevor Burnham** · Accepted Answer

This is a humdinger, but after investigating, I've got your answer:

The way coffee-script.js works is that it looks for, and runs, scripts with type="text/coffeescript" after the document has loaded. In the case of Safari, that means that

<script type="text/coffeescript">
  document.write "<h2>TEST</h2>"
</script>

is equivalent to

<script type="text/javascript">
  window.addEventListener('DOMContentLoaded', function() {
    document.write("<h2>TEST</h2>");
  }, false);
</script>

which silently fails. Note that making the insertion with the document.createElement method described by Erlend, or with a library like jQuery, will work fine.

Since this works in Chrome, I'd go ahead and call it a Safari bug. But the real moral of the story is: Don't use document.write.

document.write with CoffeeScript

UPDATE

Works on Firefox and Chrome but not in Safari

There are 2 best solutions below

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