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diff --git a/javascript.html.markdown b/javascript.html.markdown new file mode 100644 index 00000000..737638b1 --- /dev/null +++ b/javascript.html.markdown @@ -0,0 +1,114 @@ +--- +language: javascript +author: Adam Brenecki +author_url: http://adam.brenecki.id.au +--- + +Javascript was created by Netscape's Brendan Eich in 1995. It was originally +intended as a simpler scripting language for web apps, complimenting Java for +more complex ones, but has become far more widely used than Java on the web. + +Feedback would be highly appreciated! You can reach me at +[@adambrenecki](https://twitter.com/adambrenecki), or +[adam@brenecki.id.au](mailto:adam@brenecki.id.au). + +```javascript +// Comments are like C. Single-line comments start with two slashes, +/* and multiline comments start with slash-star + and end with star-slash */ + +// Statements can be terminated by ; +doStuff(); + +// ... but they don't have to be, as semicolons are automatically inserted +// wherever there's a newline, except in certain cases. +doStuff() + +// Semicolons are a heated topic in the JavaScript world, but they're really a +// matter of personal or style-guide preference. We'll leave them off here. + +/*********** + * 1. Primitive Datatypes and Operators + ***********/ + +// Javascript has one number type that covers ints and floats. +3 // = 3 +1.5 // = 1.5 + +// which support all the operations you'd expect. +1 + 1 // = 2 +8 - 1 // = 7 +10 * 2 // = 20 +35 / 5 // = 7 + +// Uneven division works how you'd expect, too. +5 / 2 # = 2.5 + +// Enforce precedence with parentheses +(1 + 3) * 2 // = 8 + +// There's also a boolean type. +true +false + +// Strings are created with ' or ". +'abc' +"Hello, world" + +// Negation uses the ! symbol +!true // = false +!false // = true + +// Equality is == +1 == 1 // = true +2 == 1 // = false + +// Inequality is != +1 != 1 // = false +2 != 1 // = true + +// More comparisons +1 < 10 #=> True +1 > 10 #=> False +2 <= 2 #=> True +2 >= 2 #=> True + +// Strings are concatenated with + +"Hello " + "world!" // = "Hello world!" + +// and are compared with < and > +"a" < "b" // = true + +// You can also compare strings with numbers +"5" == 5 // = true + +// but this is almost always not what you want, so use === to stop this +"5" === 5 // = false + +// You can access characters in a string with charAt +"This is a string".charAt(0) + +// There's also a null keyword +null // = null + +/*********** + * 2. Variables and Lists + ***********/ + +// variables are declared with the var keyword +var some_var = 5 + +// if you leave them off, you won't get an error... +some_other_var = 10 + +// but your variable will always end up with the global scope, even if it wasn't +// defined there, so don't do it. + +/*********** + * 3. Control Structures + ***********/ + +/*********** + * 4. Objects + ***********/ +``` |