var fs = require('fs'); 
var casper = require('casper').create({ 
    pageSettings: { 
        loadImages: false,     
        loadPlugins: false,    
        userAgent: 'Mozilla/5.0 (Windows NT 6.1) AppleWebKit/537.36 (KHTML, like  Gecko) Chrome/34.0.1847.137 Safari/537.36 LBBROWSER'
    }, 
    logLevel: "debug",//日志等級 
    verbose: true  // 記錄日志到控制臺 
 }); 
var url = casper.cli.raw.get('url'); 
var outputfile = casper.cli.raw.get('outputfile'); 
//請求頁面 
casper.start(url, function () { 
    fs.write(outputfile, this.getHTML(), 'w'); 
}); 
       
casper.run(); 


這里的casperjs.cli是啥意思