1. JavaScript and Ajax (JavaScript Basic) Week 2 Web site: http://fog.ccsf.edu/~hyip

2. JavaScript Basic JavaScript (aka ECMAScript) is an interpreted, object-based, scripting, loosely typed, case sensitive language There are three favors of JavaScript:  Core JavaScript: makes up of the JavaScript language  Client-side JavaScript (CSJS) = Window Object [Navigator + DOM] + Core JavaScript  Server-side JavaScript (SSJS) = compiler + Core JavaScript [HTML+JS – compiler – JS Byte code – JS interpreter – HTML]

3. JavaScript Basic (continue…) Dot notation object_name.property_name e.g. pen.inkColor = blue; document.body.style.color = red; object_name.method() e.g. pen.write("Hi"); document.write("Hello"); [See JS basic]JS basic Character set = 16-bit Unicode encoding JavaScript is case-sensitive language e.g. Document.Write("Hello"); //NOT OK JavaScript ignores white space (space, tab, new line) var a = "abc"; // OK var b = "a bc"; // NOT OK JavaScript comments // single line comment /* multiple line comments */

4. JavaScript Basic (continue…) Literals = Data value Identifiers = name (variable name, function name, label name) Identifier rules: 1)First character must be letter, or underscore (_) 2)Subsequent characters can be letter, digit, or underscore Variable declare and assign data var variable_name = "ABC"; var my_num = 123; JavaScript reserved words = words that make up of the JavaScript language. (e.g. if, else, while)

5. JavaScript Basic (continue…) Embedded JavaScript // JavaScript coding here External JavaScript [See JavaScript sample]JavaScript sample

6. JavaScript Basic (continue…) JavaScript can be in… 1. section 2. section 3.Inline with HTML as an event handler (onload, onunload, onchange, onclick, onmouseover, onmouseout) 4.Exernal JavaScript file (dir/ext_file.js) 5.Inline using JavaScript Pseudo-protocol   Or go to URL: javascript: var now = new Date(); document.write(now);