December 25, 2000 - Retrieving Objects | WebReference

December 25, 2000 - Retrieving Objects

Yehuda Shiran December 25, 2000
Retrieving Objects
Tips: December 2000

Yehuda Shiran, Ph.D.
Doc JavaScript

The worst habit to overcome when scripting Netscape 6 is how to reference HTML objects. Internet Explorer has turned us into spoiled scripters. The following HTML tag, for example:

<P ID="foo"><I>Be sure to close this paragraph.</I></P>

renders as follows:

Be sure to close this paragraph.

We can reference this tag in Internet Explorer just by its ID. For example, to figure out its location we state:

foo.style.left
This doesn't work in Netscape 6. You cannot access objects just by their HTML ID. You need to use: 

document.getElementById()
to find the object, and only then compute the object's properties. The following button calls handleClick() upon clicking:

<SCRIPT LANGUAGE="JavaScript">
<!--
function handleClick(){
  var obj = document.getElementById("button1");
  alert("horizontal position = " + obj.style.left);
}
// -->
</SCRIPT>

The following works as well:

<SCRIPT LANGUAGE="JavaScript">
<!--
function handleClick(){
  alert("horizontal position = " + document.getElementById("button1").style.left);
}
// -->
</SCRIPT>