Differences

This shows you the differences between two versions of the page.

--- notes:javascript_cheat_sheet [2008/09/04 17:12]
smthng
+++ notes:javascript_cheat_sheet [2008/09/07 02:39] (current)
smthng
@@ Line 8: / Line 8: @@
   * JavaScript is the most popular scripting language on the internet and works in all major browsers.
-  * It is a lightweight, interpreted language that is embedded into webpages to add interactivity.
+  * It is a lightweight, interpreted, object-oriented language that is embedded into webpages to add interactivity.
   * JavaScript can read and write HTML page elements, react to events, validate data, create cookies.
   * JavaScript was invented by Brendan Eich of Netscape but is now known officially as ECMAScript (current version is ECMA-262).
@@ Line 45: / Line 45: @@
   * function name(var1,var2,...) {}
   * \", \n, \t, \r, \', \&, \\
+  * with (object) { } changes default object for fields.
-==== Events, Error Handling and Popups ====
+==== Events, Error Handling & Popups ====
   *  try { throw "errname"; } catch(err) {}
   * onerror=handleErr; handleErr(msg,url,linenum)
@@ Line 62: / Line 63: @@
     * onkeydown, onkeypress, onkeyup
     * onmousedown, onmouseup
+==== JavaScript Objects ====
+  * Objects have properties and methods.
+  * Objects can be created directly <code javascript>
+personObj=new Object();
+personObj.firstname="John";
+personObj.newfirstname =
+ function (new_firstname)
+   { this.firstname=new_firstname; } </code>
+  * Objects can be created using a template <code javascript>
+function person(firstname) {
+  this.firstname=firstname;
+  this.newfirstname =
+    function (new_firstname)
+    { this.firstname=new_firstname; }
+}
+myFather=new person("John");</code>
+  * Object methods can also be assigned by name e.g. <code javascript>
+function person(firstname)
+{
+  this.firstname=firstname;
+  this.newfirstname=newfirstname;
+}
+function newfirstname(new_firstname)
+{ this.firstname=new_firstname; } </code>
+==== Predefined Objects ====
+  * String objects have a length property and methods including: indexOf, match, replace
+  * new Date() creates a Date object (with today's date).
+  * Date objects include methods: getTime(epoch), setFullYear, toUTCString, getDay, getHours
+  * Date objects can be compared using <, > .
+  * To declare an array <code javascript> var mycars=new Array("Saab","Volvo","BMW");</code>
+  * Arrays have methods including: sort, concat, join.
+  * To sort an integer array, must use a function <code javascript> function intSort (a, b){ return a - b;}</code>
+  * The Math object contains common math routines: round, random, e, pi etc.
+  * The RegExp object supports regexp creation and searching including methods: test (t/f), exec, compile (alter).
+  * HTML DOM objects allow access to browser and webpage.
+==== Advanced JavaScript ====
+  * navigator.appName/appVersion contain the browser name and version.
+  * document.cookie allows read and write access to cookie so to set a cookie <code javascript>
+function setCookie(c_name,value,expiredays)
+{
+  var exdate=new Date();
+  exdate.setDate(exdate.getDate()+expiredays);
+  document.cookie=c_name+ "=" +escape(value)+
+    ((expiredays==null) ? "" :
+     ";expires="+exdate.toGMTString());
+} </code>
+  * The onsubmit event can be used to validate a form.
+  * document.img_name.src ="pic.gif" changes an image.
+  * To change the content of a block with a given id : <code javascript>
+document.getElementById("block_id").innerHTML=txt;</code>
+  * To set or clear a timed action: <code javascript>
+var t=setTimeout("javascript statement",milliseconds);
+clearTimeout(t); </code>