A re-introduction to JavaScript - MDC

https://developer.mozilla.org/en/a_re-introduction_to_javascript

by samueladam • 17 years ago

82 17 17 years ago

developer.mozilla.org

samueladam• 17 years ago

credits to boucher: http://news.ycombinator.com/item?id=601926

axod3• 17 years ago

If you can't do anything without a book (Like me), get "JavaScript: The Definitive Guide by David Flanagan"

I know you can print things out and bind them but it's just not the same.

strider24• 17 years ago

I thought I was the only one who needed books. I can't read long articles/tutorials online and always take a print or get a book.

IsaacSchlueter• 17 years ago

Crockford's "Javascript: The Good Parts" (aka "the butterfly book") is a much quicker read, and will result in better code.

axod3• 17 years ago

I disagree. Probably a good idea to get both though. "The Good Parts" is interesting, but doesn't have a complete language reference.

Hexstream• 17 years ago

Having almost no Javascript experience, I always thought the language looked messy but with this great introduction everything seems so clear.

I found an error:

  switch(1 + 3):
      case 2 + 2:
          yay();
          break;
      default:
          neverhappens();
  }

The ":" after the first line should be a "{".

Sephr2• 17 years ago

MDC is a public wiki that anyone can edit. You can fix or change anything if you see fit (you don't need to fix it now, I fixed it).

svat• 17 years ago

This a good introduction, but Douglas Crockford's A Survey of the JavaScript Programming Language [http://javascript.crockford.com/survey.html] is shorter and more detailed — and a perfectly adequate introduction if you already know other programming languages.

Sephr2• 17 years ago

It seems that the wiki page doesn't say anything about the `delete` and `let` operators. Those are very useful operators that should be read about. (just search `delete` or `let` on MDC)

grayrest• 17 years ago

Note that `let` was introduced in Javascript 1.7 and is not available in other browser implementations.

boucher2• 17 years ago

delete can be useful, but it's not nearly as useful as it sounds. delete's only purpose is to remove a property name from an object. that is the only advantage it has over just nulling out a reference directly, and in most cases, the two techniques can be used interchangeably with no negative side effects.

let is not useful to anyone doing browser based javascript work, because it doesn't work in any browser other than Firefox and derivatives. Getting a slightly different scope behavior is hardly worth throwing out 70-80% of potential users.

axod3• 17 years ago

Wrong. It's amazing this myth still gets perpetuated. Setting something to null, or even undefined, does not delete it. That's a swift ticket to leaking memory. Use delete. It's what it's for.

  >>> var test={foo:123}
  >>> test.foo = undefined
  >>> for (var i in test) { console.log(i); }
  foo
  >>> delete test.foo
  true
  >>> for (var i in test) { console.log(i); }

ubernostrum• 17 years ago

Keep in mind that a significant proportion of cool JS features described on MDC are typically only available in recent builds of Gecko-based browsers. The baseline you can rely on in other browsers does not include let, getters/setters, comprehensions, etc., etc.

lut4rp• 17 years ago

Also on HN, http://javascript.infogami.com/Javascript_in_Ten_Minutes, is another good article.

simonw• 17 years ago

Cool, I wrote these notes up for a conference tutorial I gave a few years ago, glad to see they've taken on a useful life of their own.

tzury• 17 years ago

after 3 years of javascripting it still good to get a refresh for the language's core elements.

A re-introduction to JavaScript - MDC

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