December 13, 2000 - Setting Element Coordinates | WebReference

December 13, 2000 - Setting Element Coordinates

Yehuda Shiran December 13, 2000
Setting Element Coordinates
Tips: December 2000

Yehuda Shiran, Ph.D.
Doc JavaScript

The browser-independent W3C Standard's way to set and get an element position is via the style object's left and top properties. Although these properties denote physical measurements, they are strings. The string includes a number followed by the string "px". The following strings are example values of the left and top properties: 50px, 32px, and 0px. When setting these properties, concatenate the "px" string to the value. For example, to set the left property of an element with ID="counter1" to xlocation, you will write:

document.getElementById('counter1').style.left = xlocation + "px";

The browser won't complain if you omit the "px" string:

document.getElementById('counter1').style.left = xlocation;

The browser assumes the unit of measure is pixels and will add the "px" automatically. You'll always get a "px" ended string when querying the top and left properties.