spacer
Yehuda Shiran February 10, 2001
Passing Parameters in JavaScript
Tips: February 2001

Yehuda Shiran, Ph.D.
Doc JavaScript

Developer News
News Flash: Adobe Has iPhone Workaround
Adobe's Flash 10.1 Goes Mobile (Minus iPhone)
A Salute to Visionary CEOs

Some C++ programmers expect JavaScript to support passing parameters by reference. When we pass a parameter by reference, we pass the address of the parameter instead of its value. Once inside the function, we can change the stored value in this address. If JavaScript would have supported passing by reference, the following script would have resulted in an alert box showing the value of 6 (3 is passed to the function change() where it is doubled):

<SCRIPT LANGUAGE="JavaScript">
var a = 3;
change(a);
alert(a);

function change(value) {
  value = value * 2;
}

</SCRIPT>
But JavaScript does not support passing by reference. It passes its parameters by value only. A function does not have any way to know the address of its parameters, and hence cannot change the stored parameter value. The script above generates an alert box with the value of 3, as the variable a is not being changed by the function change().


People who read this tip also read these tips:

Look for similar tips by subject:

internet.commediabistro.comJusttechjobs.comGraphics.com

Search:

WebMediaBrands Corporate Info

Legal Notices, Licensing, Reprints, Permissions, Privacy Policy.
Advertise | Newsletters | Shopping | E-mail Offers | Freelance Jobs

webref The latest from WebReference.com Browse >
Building a Banking Application Home Page with OOP · Mixing Scripting Languages · Review: phpFox, a Social Networking CMS with all the Bells and Whistles
Sitemap · Experts · Tools · Services · Email a Colleague · Contact FREE Newsletters 
 The latest from internet.com
Enterprise 2.0: Social Networking in the Cloud · BroadSoft Marketplace Hastens Pace of Telephony Innovation · Review: HTC Hero for Sprint