Variables...
are names assigned to JavaScript statements. They may contain any letter, numeral or the _ underscore character, but may not contain any of JavaScript's reserved words. They are case sensitive.Variables must be declared within the script. This can be done by simply stating a value for the variable, or using the reserved word var.
| legal variables | illegal variables | initializing variables |
| myVariable | my Variable | var myVariable |
| mytest_ | my*test | var mytest_ = new Array() |
| duck | DUCK-Fart | duck = document.forms[0].elements[0].value |
A variables scope is determined by where it is declared. Variables that are declared outside of any functions are global, and can be used by any function. Variables declared within a function are local to that function, and child functions nested within it.
Control Structures...
provide the backbone of performing JavaScript operations. They instruct your script how to perform the task it is given. These structures take on decision making and looping.
| Object Manipulation Statements | ||
| for...in | loop through a single object | |
| label | labels a statement | |
| new | creates a new instance of an object | |
| this | specifies the current object | |
| switch...case | to test an object for multiple conditions | |
| Operators | ||
| Arithmetic | +, -, *, /, %, ++, --, - | |
| Assignment | =, +=, -=, *=,/=, %= | |
| Bitwise | and(&), or( | ), or(^), <<, >>>, >> | |
| Comparison | ==, !=, >, <, >=, <= | |
| Boolean | &&, ||, ! | |