javascript - JScript 有帮助吗？这段 JavaScript 代码的主要目的是什么？

Question

以下 JavaScript 代码的主要用途是什么？

<script>

var QunarUtil=new function(){var prefix='/scripts/';var suffix='';var host='';if(location.host.indexOf('src.')!=-1){prefix='/scripts/src/';host='http://hstatic.qunar.com';suffix='.js';}else if(location.host.indexOf('enc.')!=-1){prefix='/scripts/';host='http://hstatic.qunar.com';suffix='.js';}else if(location.host.substring(0,10)=='sdev-'){prefix=location.host.substring(5,location.host.indexOf('.'));prefix='/'+prefix.replace(/\-/ig,'/');host='http://hstatic.qunar.com';suffix='.js';}else if(location.host.indexOf("h.qunar.com")!=-1){host='http://hstatic.qunar.com';suffix='';}
this.getScriptURL=function(name,isList){if(name.charAt(0)!='/')
return this.getScript(prefix+name,isList);else
return this.getScript(name,isList);}
this.getScript=function(src,isList){return'<'+'script type="text/javascript" src="'+host+src+(isList?suffix:'.js')+'?'+__QUNARVER__+'"></'+'script>';}
this.writeScript=function(name,isList){document.write(this.getScriptURL(name,isList));}
this.writeScriptList=function(list){for(var i=0;i<list.length;i++)
document.write(this.getScriptURL(list[i]));}
var cssRoot='/styles/';this.writeCSS=function(cssList){for(var i=0;i<cssList.length;i++){document.write('<link rel="stylesheet" href="'+cssRoot+cssList[i]+'?'+__QUNARVER__+'">');}}
this.writeStaticScript=function(src){document.write('<scr'+'ipt type="text/javascript" src="'+src+'"></'+'scr'+'ipt>');}
this.writeStaticList=function(src){document.write('<scr'+'ipt type="text/javascript" src="'+src+suffix+'?'+__QUNARVER__+'"></'+'scr'+'ipt>');}}
$include=function(){for(var i=0;i<arguments.length;i++){QunarUtil.writeScript(arguments[i],true);}}
</script>

<小时/>

未压缩版本:

<script>
    var QunarUtil = new
    function() {
        var prefix = '/scripts/';
        var suffix = '';
        var host = '';
        if (location.host.indexOf('src.') != -1) {
            prefix = '/scripts/src/';
            host = 'http://hstatic.qunar.com';
            suffix = '.js';
        } else if (location.host.indexOf('enc.') != -1) {
            prefix = '/scripts/';
            host = 'http://hstatic.qunar.com';
            suffix = '.js';
        } else if (location.host.substring(0, 10) == 'sdev-') {
            prefix = location.host.substring(5, location.host.indexOf('.'));
            prefix = '/' + prefix.replace(/\-/ig, '/');
            host = 'http://hstatic.qunar.com';
            suffix = '.js';
        } else if (location.host.indexOf("h.qunar.com") != -1) {
            host = 'http://hstatic.qunar.com';
            suffix = '';
        }
        this.getScriptURL = function(name, isList) {
            if (name.charAt(0) != '/') return this.getScript(prefix + name, isList);
            else
            return this.getScript(name, isList);
        }
        this.getScript = function(src, isList) {
            return '<' + 'script type="text/javascript" src="' + host + src + (isList ? suffix : '.js') + '?' + __QUNARVER__ + '"></' + 'script>';
        }
        this.writeScript = function(name, isList) {
            document.write(this.getScriptURL(name, isList));
        }
        this.writeScriptList = function(list) {
            for (var i = 0; i < list.length; i++)
            document.write(this.getScriptURL(list[i]));
        }
        var cssRoot = '/styles/';
        this.writeCSS = function(cssList) {
            for (var i = 0; i < cssList.length; i++) {
                document.write('<link rel="stylesheet" href="' + cssRoot + cssList[i] + '?' + __QUNARVER__ + '">');
            }
        }
        this.writeStaticScript = function(src) {
            document.write('<scr' + 'ipt type="text/javascript" src="' + src + '"></' + 'scr' + 'ipt>');
        }
        this.writeStaticList = function(src) {
            document.write('<scr' + 'ipt type="text/javascript" src="' + src + suffix + '?' + __QUNARVER__ + '"></' + 'scr' + 'ipt>');
        }
    }
    $include = function() {
        for (var i = 0; i < arguments.length; i++) {
            QunarUtil.writeScript(arguments[i], true);
        }
    }
</script>

Answer 1

它是一个从 http://hstatic.qunar.com 加载 JavaScript 和 CSS 文件的实用程序.

按原样，该代码将无法工作，因为它依赖于一个名为 __QUARVER__

的全局变量

下面是带有内联文档的代码版本。

//Expose the variable QunarUtil into the global namespace, which is an instance of an anonymous function.
var QunarUtil = new function() {
    //set up internal variable in QunarUtil
    var prefix = '/scripts/';
    var suffix = '';
    var host = '';
    //Modify prefix, host & suffix if the current host (think webpage server
    //address in the browser) has 'src.' as part of it's hostname.
    if (location.host.indexOf('src.') != -1) {
        prefix = '/scripts/src/';
        host = 'http://hstatic.qunar.com';
        suffix = '.js';
    //Modify prefix, host & suffix if the current host has 'enc.' as part of it's hostname.
    } else if (location.host.indexOf('enc.') != -1) {
        prefix = '/scripts/';
        host = 'http://hstatic.qunar.com';
        suffix = '.js';
    //Modify prefix, host & suffix if the current host is 'sdev-' (and nothing
    //else since it is comparing a 5 char string with 10 char substring).
    } else if (location.host.substring(0, 10) == 'sdev-') {
        prefix = location.host.substring(5, location.host.indexOf('.'));
        prefix = '/' + prefix.replace(/\-/ig, '/');
        host = 'http://hstatic.qunar.com';
        suffix = '.js';
    //Modify prefix, host & suffix if the current host has 'h.qunar.com' as part of it's hostname.
    } else if (location.host.indexOf("h.qunar.com") != -1) {
        host = 'http://hstatic.qunar.com';
        suffix = '';
    }
    //Expose a method on the QunarUtil variable called getScriptURL.
    this.getScriptURL = function(name, isList) {
        if (name.charAt(0) != '/')
            return this.getScript(prefix + name, isList);
        else
            return this.getScript(name, isList);
    }
    //Expose a method on the QunarUtil variable called getScript.
    this.getScript = function(src, isList) {
        return '<' + 'script type="text/javascript" src="' + host +
               src + (isList ? suffix : '.js') + '?' + __QUNARVER__ + '"></' + 'script>';
    }
    //Expose a method on the QunarUtil variable called writeScript.
    this.writeScript = function(name, isList) {
        document.write(this.getScriptURL(name, isList));
    }
    //Expose a method on the QunarUtil variable called writeScriptList.
    this.writeScriptList = function(list) {
        for (var i = 0; i < list.length; i++)
        document.write(this.getScriptURL(list[i]));
    }
    //Set a new internal QunarUtil variable.
    var cssRoot = '/styles/';
    //Expose a method on the QunarUtil variable called writeCSS.
    this.writeCSS = function(cssList) {
        for (var i = 0; i < cssList.length; i++) {
            document.write('<link rel="stylesheet" href="' + cssRoot + cssList[i] + '?' + __QUNARVER__ + '">');
        }
    }
    //Expose a method on the QunarUtil variable called writeStaticScript.
    this.writeStaticScript = function(src) {
        document.write('<scr' + 'ipt type="text/javascript" src="' + src + '"></' + 'scr' + 'ipt>');
    }
    //Expose a method on the QunarUtil variable called writeStaticList.
    this.writeStaticList = function(src) {
        document.write('<scr' + 'ipt type="text/javascript" src="' + src + suffix +
                       '?' + __QUNARVER__ + '"></' + 'scr' + 'ipt>');
    }
}
//Expose a global variable called $inclue which take an arbitrary number
//of JavaScript-file URLs as string arguments and loops over them to
//create a bunch of <script> tags using the QunarUtil.writeScript method.
$include = function() {
    for (var i = 0; i < arguments.length; i++) {
        QunarUtil.writeScript(arguments[i], true);
    }
}

此代码与您喜欢的 float Google map 无关，但它可能用于加载相关代码。