A Simple, Comprehensive Overview of Javascript

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#1

This isn’t a reference guide, programming tutorial or detailed overview. It’s a Javascript refresher, assuming you know another programming language and puts all the information in one place (just ctrl+f to find!). Javascript has nothing to do with Java, is dynamically typed and has **C-like syntax

This is a companion discussion topic for the original entry at http://betterexplained.com/articles/the-single-page-javascript-overview/
#2

This is good. I like your spirit!

#3

So we can use objects like associative arrays in php. Nice.

#4

Yep, that’s a good point. I use javascript objects as a hash table (associative array) quite often.

#5

[…] A bookmarklet can use any javascript command, but certain ones are helpful: […]

#6

Yeaah it’s very simple and comprehensive Overview.

Thanks

#7

var obj = { // create object using JSON
name: “Bob”, // aka Javascript Object Notation
details: {
age: 33,
“favorite color”: “green”
}
}
obj.name
obj.details[“favorite color”]

i’ve a question… how can I print all obj property without know them
exist something like reflection???
I’m looking for a function like (php) print_r(obj)

#8

@Steal: You’d have to iterate through all the properties on the object and print them out:

for(prop in obj)
{
str += prop + “value :” + obj[prop]+"\n";
}

See http://vijayk.wordpress.com/2006/12/14/for-in-loop-to-print-object-properties-with-javascriptactionscript/

#9

In line 4 of your sample for the section “Comparisons and Manipulations,” it seems to me that you’re missing a ‘=’.

#10

@Anonymous: Whoops! Yep, you’re correct, fixed now. Thanks!

#11

Thank you!
I am new to Javascript and you have given me good starting point. I find it so easy to follow JS now.

Thanks!

#12

Thanks Samuel, great catch! Just updated to clarify.

#13

These lines are not quite correct:

var str = “Hello”; // local variable
str2 = “Hello World”; /* global */

While “var” is the correct way to define a variable in the local scope, in this case both “str” and “str2” will become properties of the “window” object, which is essentially JavaScript’s global scope. A function is the only way to create a new local scope in JS, so “var” is only useful inside functions (and all JS code should be inside a function to prevent polluting the global scope).

#14

When describing constructor functions you use self without defining it. Its probably better to just use this.

#15

the redirect when JavaScript is disabled sounds like a pretty good idea, however I’ve heard before that meta redirects are viewed negatively by Google and other search engines. If you’re using PHP maybe you could do a redirect with that inside the noscript tag. (or whichever server side programming language you prefer.)
Nice to see such an article recently posted somewhere and up voted 6 years after it was originally published…

#16

@devurls: Interesting point, not sure about the SEO impact. Yep, I like that this is still handy for people!

@Michael, Adam: Thanks, great feedback. Just changed.

#17

In you “Javascript Classes” section, “self.setName” should be “this.setName”. Otherwise, a nice summary!

#18

[…] http://betterexplained.com/articles/the-single-page-javascript-overview/ […]

#19

Simply awesome man