Kevin Reuter & Brian Guthrie

 Multi-paradigm  Prototype based objects  Dynamic, weak typing

1995  Originally developed for Netscape as 'Mocha' by Brendan Eich  Renamed to LiveScript when it was first included in Navigator  Renamed again to JavaScript  Final renaming coincided with Navigator adding support for Java - confusion ensued 1996  Microsoft includes JScript in IE 3  Netscape submits JS to ECMA for standards consideration  Standard adopted in 1997

 JavaScript  Jscript  Jscript.NET  ECMAScript  ActionScript  QtScript  Objective-J  WMLScript

 Primitive Datatypes  String: ‘single quote’ “and double quote”  Boolean: true, false  Number: 1, 2.0  Special Types  null  undefined  NaN  Infinity

 Pros  C-style syntax  Style is not subjective  Cons  Nested function  Dynamically typed variables  Minimal variable naming rules

 Pros  Semicolon insertion  Dynamically typed variables  Cons  Semicolon insertion  Style is not subjective

 Pros  Most browsers have built-in debugging consoles  Cons  Dynamically typed variables  Scripts are run in client browser  Easily exploitable (XSS, CSRF)  Inclusion in web pages can cause T2S and magnification features to fail

 Pros  Scripts are run in client browser  C-based syntax is commonly known  Cons  Many different variations  Every browser family has its own version  May have to write separate code for each  Prototype-base languages are uncommon  Based on Scheme

 Cons  Undefined variables are undefined not null  All numbers are IEEE-745 doubles  =  So !=.3  Strings can be single or double quoted  var greeting = "Hello, world!";  var greeting = 'Hello, world!';  Many vendor-specific variations  Semicolon insertion  with (…) {}  Seriously?" \t \r\n " == 0 == ‘0’ == false != ‘false’

 Serialization format based on JS object shorthand  Used as an alternative to XML

 Cross-site vulnerabilities  Insertion of malicious JavaScript into a site  Misplaced trust in client browser  No reliable way to hide code from clients  Scripts can be disabled so JS can't be used to prevent certain actions  Browser and plugin coding errors  Coding errors in plugins can allow for things like buffer- overflows  Sandbox implementation errors  Browser can unintentionally allow JS to run outside of a sandbox  Windows allows JS to be run as a non-sandboxed, general- purpose program

 The Internet - just turn off JS in your web browser and watch the web stop working.  Many other programming languages have libraries for manipulating JSON.

 "JS had to 'look like Java' only less so, be Java’s dumb kid brother or boy-hostage sidekick. Plus, I had to be done in ten days or something worse than JS would have happened" - Brendan Eich  “The problem with JavaScript isn’t just that it allows them (global variables), it requires them.” – Douglas Crockford  “All JavaScript implementations are broken. Some more broken than others [...]. They're all broken in different ways.” - Bob Ippolito

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