Some Other JavaScript Sources On IDM
· JavaScript FAQ
· Basic JavaScript with Examples
·   Javascript Event Handlers
·   Putting JavaScript to Work
·   eXchange Thread: Javascript for Date Last Changed & Y2K
·   JS/Configurator: A Computer Cost Estimator
·   A Look at JavaScript in Microsoft IE vs. Netscape Communicator
·   JavaScript Forms and Frames: Enhancing HTML on the Client Side
·   JS/Configurator: A Computer Cost Estimator

Tutorial: Introduction to JavaScript

By Aaron Weiss

Operators

Object manipulation

for...in

The sometimes confusing for...in statement is used to cycle through each property of an object or each element of an array. The idea is that you may want to execute a statement block which operates on every property or element.

for (variable in object) 
 { statements; }

Imagine, for example, that an object named wine1 has five properties: vineyard, year, varietal, alcohol, and color. You want to output the value of each property, as if producing a record from a database.

var record = "Wine 1<br><br>"
for (var prop in wine1)
 {record += prop + " = " + wine1[prop] + "<BR>"}
record += "<br>"
document.write(record)

with

The with statement serves as a sort of shorthand, allowing you to execute a series of statement who all assume a specified object as the reference. In other words, the object specified in the with statement is used as the default object whenever a property is encountered with no object specified.

with (object) 
 { statements; }

JavaScript Tutorial [Previous: Loops | Next: Comments]