JavaScript Flow Control

This page lists the basic forms of JavaScript flow control.

Conditionals

if (test) {...} else {...}

switch (expr1){
   case val1 : 
      ...
      break;
   case val2 : 
      ...
      break;
   ...
   default : statement;
}

The break statement prevents any further check. Without the “break”, the check goes on, and will execute the block if there's match again.

Loops

for (i=0; i<10; i++) { ... }

for (var myVal in someObject) { ... myVal ...}

do {...} while (...)

while (...) {...}

“continue” exit the current iteration in a loop. (that is, start the next iteration at the beginning of loop)

Object Property

with (myObject) { ... }

A shortcut so that properties of myObject in the body block needs not have prefix “myObject.”

Comments

comments is:

// this is comment or
/* comment here */

In JavasSript, the ending semicolon is optional if it is at end of a line.

Reference: http://msdn2.microsoft.com/en-us/library/3xcfcb93.aspx

See also:

• Data Types
• Operators
• Defining Functions

Page created: 2005-05.
© 2005 by Xah Lee.