<?xml version = '1.0' encoding = 'utf-8'?> <!DOCTYPE html PUBLIC "-//WAPFORUM//DTD XHTML Mobile 1.0//EN" "http://www.wapforum.org/DTD/xhtml-mobile10.dtd"> <html xmlns="http://www.w3.org/1999/xhtml"> <head> <script> function doTest() { var Ci = Components.interfaces; var defaultZoom = {}, allowZoom = {}, minZoom = {}, maxZoom ={}, width = {}, height = {}, autoSize = {}; var windowUtils = window.QueryInterface(Ci.nsIInterfaceRequestor).getInterface(Ci.nsIDOMWindowUtils); windowUtils.getViewportInfo(1, 1, defaultZoom, allowZoom, minZoom, maxZoom, width, height, autoSize); document.getElementById("minZoom").innerHTML = minZoom.value.toPrecision(10); document.getElementById("maxZoom").innerHTML = maxZoom.value.toPrecision(10); } </script> </head> <body onload="doTest();"> MinZoom: <span id="minZoom"></span><br /> MaxZoom: <span id="maxZoom"></span> </body> </html>