A, java script: scripting language to parse and executed by the browser
1. Weak Type - corresponds to a strongly typed
Weakly typed variable is defined is not required when the declared data type, the data type is a variable value determined.
In strongly typed variable definition when it has the data to determine the type.
Two, java script to use
(1) handles writing
(2) internal style sheet (<script> js Code </ script>)
(3) an external style sheet (<script src = "js js file ends with"> </ script>)
(4) introducing external module
Three, (1) the original data type: number (number) String (String) Boolean (Boolean) undefined (undefined) null (empty)
(2) reference data types: object (Object) var d = true (Boolean) var g = null (the placeholder object)
* 1. Any type with string concatenation, are spliced string.
2. Digital and Boolean type, an implicit conversion. True converted into converted into 0 1.false.
3. The digital type and type of operation is not (except string, Boolean). Adding unsuccessful appear NAN
Fourth, the frame shells are built in JavaScript (developer already defined) to a function.
Function is for us to call.
Three kinds of bomb box: alert alert box
Enter the prompt pop-up box
confirm the pop-up box OK Cancel