!function(a,b)(pa, pb);
等同于(function(a,b))(pa, pb);

分析一：jQuery的无new构建

JavaScript是函数式语言，函数可以实现类，类就是面向对象编程中最基本的概念

复制代码
var aQuery = function(selector, context) {
        //构造函数
}
aQuery.prototype = {
    //原型
    name:function(){},
    age:function(){}
}

var a = new aQuery();

a.name();



var aQuery = function(selector, context) {
   return  aQuery.prototype.init();
}
aQuery.prototype = {
    init:function(){
        return this;
    }
    name:function(){},
    age:function(){}
}



A = n.fn.init = function(a, b) {
        var c, d;
        if (!a) return this;
        if ("string" == typeof a) {
            if (c = "<" === a[0] && ">" === a[a.length - 1] && a.length >= 3 ? [null, a, null] : z.exec(a), !c || !c[1] && b) return ! b || b.jquery ? (b || y).find(a) : this.constructor(b).find(a);
            if (c[1]) {
                if (b = b instanceof n ? b[0] : b, n.merge(this, n.parseHTML(c[1], b && b.nodeType ? b.ownerDocument || b: l, !0)), v.test(c[1]) && n.isPlainObject(b)) for (c in b) n.isFunction(this[c]) ? this[c](b[c]) : this.attr(c, b[c]);
                return this
            }
            return d = l.getElementById(c[2]),
            d && d.parentNode && (this.length = 1, this[0] = d),
            this.context = l,
            this.selector = a,
            this
        }
        return a.nodeType ? (this.context = this[0] = a, this.length = 1, this) : n.isFunction(a) ? "undefined" != typeof y.ready ? y.ready(a) : a(n) : (void 0 !== a.selector && (this.selector = a.selector, this.context = a.context), n.makeArray(a, this))
    };
A.prototype = n.fn,