Javascript: Common Function

CommonFunction.js

// CommonFunction.js
// Author Kenji Wong
// Lastest Modification 16/11/2012

if(!window.console) window.console = { log: function(){ return; } };

var classExtend = function(subClass, superClass) {
    var F = function() {};
    F.prototype = superClass.prototype;
    subClass.prototype = new F();
    subClass.prototype.constructor = subClass;
    subClass.superclass = superClass.prototype;
    if(superClass.prototype.constructor == Object.prototype.constructor) {
        superClass.prototype.constructor = superClass;
    }
};
var preloadImageArray = function(pImageArray, pCallback){
    if (document.images){
        var imageCount_num = pImageArray.length;
        var imageObj_array = [];
        var imageLoaded_num = 0;
        for(var i=0; i<imageCount_num; i++){
            var image_obj = new Image();
            image_obj.src = pImageArray[i];
            image_obj.onload = function(){
                imageObj_array.push(this);
                imageLoaded_num += 1;
                if(imageLoaded_num == pImageArray.length)
                    pCallback(imageObj_array);
            };
        }
    }
};
var checkViewPort = function(){
    var navigateUA = navigator.userAgent;
    if ((navigateUA.indexOf('iPhone') == -1) && (navigateUA.indexOf('iPod') == -1) && (navigateUA.indexOf('iPad') == -1)){
        var e = window, a = 'inner';
        var viewport = document.querySelector("meta[name=viewport]");
        if (!('innerWidth' in window)){
            a = 'client';
            e = document.documentElement || document.body;
        }
        var initScale = new Number(e[a+"Width"] / 640);
            initScale = initScale.toFixed(1);
        viewport.setAttribute('content', 'width=device-width, minimum-scale=0.5, initial-scale='+initScale);
    }
};