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请问这一段JS是怎么压缩的?

0
悬赏园豆:5 [已解决问题] 解决于 2012-05-12 13:07

下面是压缩后的JS:

eval(function(p,a,c,k,e,r){e=function(c){return(c<a?'':e(parseInt(c/a)))+((c=c%a)>35?String.fromCharCode(c+29):c.toString(36))};if(!''.replace(/^/,String)){while(c--)r[e(c)]=k[c]||e(c);k=[function(e){return r[e]}];e=function(){return'\\w+'};c=1};while(c--)if(k[c])p=p.replace(new RegExp('\\b'+e(c)+'\\b','g'),k[c]);return p}('m 6(a,b,c,d,e){5.u=6.$(a);7(5.u==k&&a!="n"){M y N("6(p)参数错误:p 对像存在!(Z:"+a+")")};7(!6.q){6.q=y 1r()};5.p=6.q.9;6.q.1d(5);5.1s=r;5.8=[];5.10=c==k?0:c;5.E=5.10;5.11=d==k?"1t":d;5.13=e==k?"":e;5.F=r;j f=P("6.q["+5.p+"].F = z");j g=P("6.q["+5.p+"].F = r");7(a!="n"){7(5.u.v){5.u.v("14",f)}w{5.u.Q("15",f,r)}};7(a!="n"){7(5.u.v){5.u.v("16",g)}w{5.u.Q("17",g,r)}};7(18(b)!="1u"){b="1v"};b=b.1w();1x(b){U"14":5.B="15";G;U"16":5.B="17";G;U"1y":5.B="1z";G;U"1A":5.B="1B";G;1C:5.B="1D"};5.H=r;5.A=k;5.R=1E};6.t.1F="1.1G";6.t.1H="1I";6.t.1e=m(a,b,c,d,e){7(6.$(a)==k&&a!="n"){M y N("1e(1f)参数错误:1f 对像存在!(Z:"+a+")")};j f=5.8.9;7(c==""){c=k};5.8.1d([a,b,c,d,e]);j g=P(\'6.q[\'+5.p+\'].C(\'+f+\')\');7(a!="n"){7(6.$(a).v){6.$(a).v("1J"+5.B,g)}w{6.$(a).Q(5.B,g,r)}};7(f==5.10){7(a!="n"){6.$(a).V=5.11};7(6.$(b)){6.$(b).J.W=""};7(5.p!="n"){7(c!=k){5.u.J.1g=c}};7(d!=k){S(d)}}w{7(a!="n"){6.$(a).V=5.13};7(6.$(b)){6.$(b).J.W="n"}};j h=P("6.q["+5.p+"].F = z");j i=P("6.q["+5.p+"].F = r");7(6.$(b)){7(6.$(b).v){6.$(b).v("14",h)}w{6.$(b).Q("15",h,r)};7(6.$(b).v){6.$(b).v("16",i)}w{6.$(b).Q("17",i,r)}}};6.t.C=m(a,b){7(18(a)!="19"){M y N("C(1h)参数错误:1h 不是 19 类型!(Z:"+a+")")};7(b!=z&&5.E==a){K};j i;T(i=0;i<5.8.9;i++){7(i==a){7(5.8[i][0]!="n"){6.$(5.8[i][0]).V=5.11};7(6.$(5.8[i][1])){6.$(5.8[i][1]).J.W=""};7(5.p!="n"){7(5.8[i][2]!=k){5.u.J.1g=5.8[i][2]}};7(5.8[i][3]!=k){S(5.8[i][3])}}w 7(5.E==i||b==z){7(5.8[i][0]!="n"){6.$(5.8[i][0]).V=5.13};7(6.$(5.8[i][1])){6.$(5.8[i][1]).J.W="n"};7(5.8[i][4]!=k){S(5.8[i][4])}}};5.E=a};6.t.1a=m(){7(s.9!=5.8.9){M y N("1a()参数错误:参数数量与标签数量不符!(9:"+s.9+")")};j a=0,i;T(i=0;i<s.9;i++){a+=s[i]};j b=1K.1a(),1b=0;T(i=0;i<s.9;i++){1b+=s[i]/a;7(b<1b){5.C(i);G}}};6.t.1i=m(){7(s.9!=5.8.9){M y N("1i()参数错误:参数数量与标签数量不符!(9:"+s.9+")")};7(!(/^\\d+$/).1j(6.D)){K};j a=0,i;T(i=0;i<s.9;i++){a+=s[i]};j b=6.D%a;7(b==0){b=a};j c=0;T(i=0;i<s.9;i++){c+=s[i];7(c>=b){5.C(i);G}}};6.t.1L=m(a){7(18(a)=="19"){5.R=a};X(5.A);5.A=1c("6.q["+5.p+"].Y()",5.R);5.H=z};6.t.Y=m(){7(5.H==r||5.F==z){K};5.1k()};6.t.1k=m(){j a=5.E;a++;7(a>=5.8.9){a=0};5.C(a);7(5.H==z){X(5.A);5.A=1c("6.q["+5.p+"].Y()",5.R)}};6.t.1M=m(){j a=5.E;a--;7(a<0){a=5.8.9-1};5.C(a);7(5.H==z){X(5.A);5.A=1c("6.q["+5.p+"].Y()",5.R)}};6.t.1N=m(){X(5.A);5.H=r};6.$=m(a){7(x.1l){K S(\'x.1l("\'+a+\'")\')}w{K S(\'x.1O.\'+a)}};6.1m=m(l){j i="",I=l+"=";7(x.L.9>0){j a=x.L.1n(I);7(a!=-1){a+=I.9;j b=x.L.1n(";",a);7(b==-1)b=x.L.9;i=1P(x.L.1Q(a,b))}};K i},6.1o=m(O,o,l,I){j i="",c="";7(l!=k){i=y 1p((y 1p).1R()+l*1S);i="; 1T="+i.1U()};7(I!=k){c=";1V="+I};x.L=O+"="+1W(o)+i+c};6.D=6.1m("1q");7((/^\\d+$/).1j(6.D)){6.D++}w{6.D=1};6.1o("1q",6.D,12);',62,121,'|||||this|SubShowClass|if|label|length||||||||||var|null||function|none||ID|childs|false|arguments|prototype|parentObj|attachEvent|else|document|new|true|autoPlayTimeObj|eventType|select|sum|selectedIndex|mouseIn|break|autoPlay||style|return|cookie|throw|Error||Function|addEventListener|spaceTime|eval|for|case|className|display|clearInterval|autoPlayFunc|value|defaultID|openClassName||closeClassName|onmouseover|mouseover|onmouseout|mouseout|typeof|number|random|percent|setInterval|push|addLabel|labelID|background|num|order|test|nextLabel|getElementById|readCookie|indexOf|writeCookie|Date|SSCSum|Array|lock|selected|string|onmousedown|toLowerCase|switch|onclick|click|onmouseup|mouseup|default|mousedown|5000|version|30|author|mengjia|on|Math|play|previousLabel|stop|all|unescape|substring|getTime|3600000|expires|toGMTString|domain|escape'.split('|'),0,{}))

格式化后是这样的:

function SubShowClass(a, b, c, d, e) {
    this.parentObj = SubShowClass.$(a);
    if (this.parentObj == null && a != "none") {
        throw new Error("SubShowClass(ID)参数错误:ID 对像存在!(value:" + a + ")")
    };
    if (!SubShowClass.childs) {
        SubShowClass.childs = new Array()
    };
    this.ID = SubShowClass.childs.length;
    SubShowClass.childs.push(this);
    this.lock = false;
    this.label = [];
    this.defaultID = c == null ? 0 : c;
    this.selectedIndex = this.defaultID;
    this.openClassName = d == null ? "selected" : d;
    this.closeClassName = e == null ? "" : e;
    this.mouseIn = false;
    var f = Function("SubShowClass.childs[" + this.ID + "].mouseIn = true");
    var g = Function("SubShowClass.childs[" + this.ID + "].mouseIn = false");
    if (a != "none") {
        if (this.parentObj.attachEvent) {
            this.parentObj.attachEvent("onmouseover", f)
        } else {
            this.parentObj.addEventListener("mouseover", f, false)
        }
    };
    if (a != "none") {
        if (this.parentObj.attachEvent) {
            this.parentObj.attachEvent("onmouseout", g)
        } else {
            this.parentObj.addEventListener("mouseout", g, false)
        }
    };
    if (typeof (b) != "string") {
        b = "onmousedown"
    };
    b = b.toLowerCase();
    switch (b) {
    case "onmouseover":
        this.eventType = "mouseover";
        break;
    case "onmouseout":
        this.eventType = "mouseout";
        break;
    case "onclick":
        this.eventType = "click";
        break;
    case "onmouseup":
        this.eventType = "mouseup";
        break;
    default:
        this.eventType = "mousedown"
    };
    this.autoPlay = false;
    this.autoPlayTimeObj = null;
    this.spaceTime = 5000
};
SubShowClass.prototype.version = "1.30";
SubShowClass.prototype.author = "mengjia";
SubShowClass.prototype.addLabel = function (a, b, c, d, e) {
    if (SubShowClass.$(a) == null && a != "none") {
        throw new Error("addLabel(labelID)参数错误:labelID 对像存在!(value:" + a + ")")
    };
    var f = this.label.length;
    if (c == "") {
        c = null
    };
    this.label.push([a, b, c, d, e]);
    var g = Function('SubShowClass.childs[' + this.ID + '].select(' + f + ')');
    if (a != "none") {
        if (SubShowClass.$(a).attachEvent) {
            SubShowClass.$(a).attachEvent("on" + this.eventType, g)
        } else {
            SubShowClass.$(a).addEventListener(this.eventType, g, false)
        }
    };
    if (f == this.defaultID) {
        if (a != "none") {
            SubShowClass.$(a).className = this.openClassName
        };
        if (SubShowClass.$(b)) {
            SubShowClass.$(b).style.display = ""
        };
        if (this.ID != "none") {
            if (c != null) {
                this.parentObj.style.background = c
            }
        };
        if (d != null) {
            eval(d)
        }
    } else {
        if (a != "none") {
            SubShowClass.$(a).className = this.closeClassName
        };
        if (SubShowClass.$(b)) {
            SubShowClass.$(b).style.display = "none"
        }
    };
    var h = Function("SubShowClass.childs[" + this.ID + "].mouseIn = true");
    var i = Function("SubShowClass.childs[" + this.ID + "].mouseIn = false");
    if (SubShowClass.$(b)) {
        if (SubShowClass.$(b).attachEvent) {
            SubShowClass.$(b).attachEvent("onmouseover", h)
        } else {
            SubShowClass.$(b).addEventListener("mouseover", h, false)
        };
        if (SubShowClass.$(b).attachEvent) {
            SubShowClass.$(b).attachEvent("onmouseout", i)
        } else {
            SubShowClass.$(b).addEventListener("mouseout", i, false)
        }
    }
};
SubShowClass.prototype.select = function (a, b) {
    if (typeof (a) != "number") {
        throw new Error("select(num)参数错误:num 不是 number 类型!(value:" + a + ")")
    };
    if (b != true && this.selectedIndex == a) {
        return
    };
    var i;
    for (i = 0; i < this.label.length; i++) {
        if (i == a) {
            if (this.label[i][0] != "none") {
                SubShowClass.$(this.label[i][0]).className = this.openClassName
            };
            if (SubShowClass.$(this.label[i][1])) {
                SubShowClass.$(this.label[i][1]).style.display = ""
            };
            if (this.ID != "none") {
                if (this.label[i][2] != null) {
                    this.parentObj.style.background = this.label[i][2]
                }
            };
            if (this.label[i][3] != null) {
                eval(this.label[i][3])
            }
        } else if (this.selectedIndex == i || b == true) {
            if (this.label[i][0] != "none") {
                SubShowClass.$(this.label[i][0]).className = this.closeClassName
            };
            if (SubShowClass.$(this.label[i][1])) {
                SubShowClass.$(this.label[i][1]).style.display = "none"
            };
            if (this.label[i][4] != null) {
                eval(this.label[i][4])
            }
        }
    };
    this.selectedIndex = a
};
SubShowClass.prototype.random = function () {
    if (arguments.length != this.label.length) {
        throw new Error("random()参数错误:参数数量与标签数量不符!(length:" + arguments.length + ")")
    };
    var a = 0,
        i;
    for (i = 0; i < arguments.length; i++) {
        a += arguments[i]
    };
    var b = Math.random(),
        percent = 0;
    for (i = 0; i < arguments.length; i++) {
        percent += arguments[i] / a;
        if (b < percent) {
            this.select(i);
            break
        }
    }
};
SubShowClass.prototype.order = function () {
    if (arguments.length != this.label.length) {
        throw new Error("order()参数错误:参数数量与标签数量不符!(length:" + arguments.length + ")")
    };
    if (!(/^\d+$/).test(SubShowClass.sum)) {
        return
    };
    var a = 0,
        i;
    for (i = 0; i < arguments.length; i++) {
        a += arguments[i]
    };
    var b = SubShowClass.sum % a;
    if (b == 0) {
        b = a
    };
    var c = 0;
    for (i = 0; i < arguments.length; i++) {
        c += arguments[i];
        if (c >= b) {
            this.select(i);
            break
        }
    }
};
SubShowClass.prototype.play = function (a) {
    if (typeof (a) == "number") {
        this.spaceTime = a
    };
    clearInterval(this.autoPlayTimeObj);
    this.autoPlayTimeObj = setInterval("SubShowClass.childs[" + this.ID + "].autoPlayFunc()", this.spaceTime);
    this.autoPlay = true
};
SubShowClass.prototype.autoPlayFunc = function () {
    if (this.autoPlay == false || this.mouseIn == true) {
        return
    };
    this.nextLabel()
};
SubShowClass.prototype.nextLabel = function () {
    var a = this.selectedIndex;
    a++;
    if (a >= this.label.length) {
        a = 0
    };
    this.select(a);
    if (this.autoPlay == true) {
        clearInterval(this.autoPlayTimeObj);
        this.autoPlayTimeObj = setInterval("SubShowClass.childs[" + this.ID + "].autoPlayFunc()", this.spaceTime)
    }
};
SubShowClass.prototype.previousLabel = function () {
    var a = this.selectedIndex;
    a--;
    if (a < 0) {
        a = this.label.length - 1
    };
    this.select(a);
    if (this.autoPlay == true) {
        clearInterval(this.autoPlayTimeObj);
        this.autoPlayTimeObj = setInterval("SubShowClass.childs[" + this.ID + "].autoPlayFunc()", this.spaceTime)
    }
};
SubShowClass.prototype.stop = function () {
    clearInterval(this.autoPlayTimeObj);
    this.autoPlay = false
};
SubShowClass.$ = function (a) {
    if (document.getElementById) {
        return eval('document.getElementById("' + a + '")')
    } else {
        return eval('document.all.' + a)
    }
};
SubShowClass.readCookie = function (l) {
    var i = "",
        I = l + "=";
    if (document.cookie.length > 0) {
        var a = document.cookie.indexOf(I);
        if (a != -1) {
            a += I.length;
            var b = document.cookie.indexOf(";", a);
            if (b == -1) b = document.cookie.length;
            i = unescape(document.cookie.substring(a, b))
        }
    };
    return i
}, SubShowClass.writeCookie = function (O, o, l, I) {
    var i = "",
        c = "";
    if (l != null) {
        i = new Date((new Date).getTime() + l * 3600000);
        i = "; expires=" + i.toGMTString()
    };
    if (I != null) {
        c = ";domain=" + I
    };
    document.cookie = O + "=" + escape(o) + i + c
};
SubShowClass.sum = SubShowClass.readCookie("SSCSum");
if ((/^\d+$/).test(SubShowClass.sum)) {
    SubShowClass.sum++
} else {
    SubShowClass.sum = 1
};
SubShowClass.writeCookie("SSCSum", SubShowClass.sum, 12);

后面那些用|隔开的是什么,有什么用?

观海云不远的主页 观海云不远 | 初学一级 | 园豆:89
提问于:2012-05-11 20:38
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最佳答案
0

这个不叫压缩,但也可以算作一种压缩。

不过是把里面的所有不想干的空白符号删除而去。

比如连续的多个空格、回车换行、tab等其实只要有一个空格替代就可以了,然后再在必要的地方插入一个分号之类的。

通过这样的压缩算法后,可以让JS的文件体积大大缩小,从而达到节省带宽的目的。否则,一个JQuery的代码库可是好几十K,这个浪费换作在几年前特别是10十年前那可是很大的。

收获园豆:5
无之无 | 大侠五级 |园豆:5085 | 2012-05-12 08:13
其他回答(1)
0

这些常用的压缩,对于一个网站,已经够用了。要是真正的压缩,会把变量啊之类的都边成abcd这样简单的字符,一样删除空白 回车之类的。

icepy | 园豆:587 (小虾三级) | 2012-05-12 10:01
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