//http小爬虫
var http=require('http')
var cheerio=require('cheerio')
var url='http://www.imooc.com/learn/348'
function filter(html){
var $=cheerio.load(html);
var chapters=$('.mod-chapters')
var courseData=[]
chapters.each(function(item){
var chapter=$(this)
var chapterTitle=chapter.find('strong').text()
var videos=chapter.find('.video').children('li')
var chapterData={
chapterTitle:chapterTitle,
videos:[]
}
videos.each(function(item){
var video=$(this).find('.stydyvideo')
var videoTitle=video.text() chapterData.videos.push({
title:videoTitle, })
})
courseData.push(chapterData)
})
return courseData
}
http.get(url,function(res){
var html=''
res.on('data',function(data){
html+=data
})
res.on('end',function(){
var data=filter(html);
console.log(data)
})
}).on('error',function(){ }) /**
* Created by Administrator on 2017-07-03.
*/
//事件模块小插曲 对一个事件不要超过10个监听器
var EventEmitter=require('events').EventEmitter
var life=new EventEmitter();
life.on('ddd',function(){
console.log('55555555')
})
life.on('ddd',function(){
console.log('6666')
})
function water(){ }
life.listeners('ddd').length//查看事件的个数
EventEmitter.listenerCount(life,'ddd')
//life.removeListener('ddd',water)//删除事件监听
life.emit('ddd')//事件触发
//删除所有的监听事件
life.removeAllListeners()