$('.someclass').show().css('xxx','xxxx').click(function(){}).xxx……

(function(){

 function _$(els){

this.elements = [];

for(var i=0, len=els.length;i<len;i++){

 var elements = els[i];

 if(typeof element = ‘string'){

  element = document.getElementByIdx_x_x(element);

}

}

this.elements.push(element);

}

_$.prototype = {

 each:function(fn){

  for(var i=0,len=this.elements.length;i<len;i++){

   fn.call(this, this.elements[i]);

}

return this;

},

setStyle: function(prop, val){

……

},

show:function(){

……

},

……

}

window.$ = function(){

 return new _$(arguments);

}

})();

/*
map()
items 遍歷的數(shù)組的每一項(xiàng)
​
*/
var arr = [1,2,3];
var num = arr.map(function(items){
  return items + 1;
});
console.log(num);//[2,3,4 var arr = [1,2,3];
    var num = arr.map(function (items) {
      return items+1;
    }).reduce(function (a,b) {//[2,3,4].reduce()
      return a+b;
    })
​
    console.log(num);//0 --- 2+3+4 = 9]
​
/* 
  reduce 實(shí)現(xiàn)數(shù)組里的每個(gè)數(shù)相加,也就是給數(shù)組的每一項(xiàng)求總和
  reduce(function(a,b){
    return a+b;
  },a)--a的初始值
*/
var arr = [1,2,3];
var num_1 = arr.reduce(function (a,b) {
  return a+b;
})
console.log(num_1);//6
​
/* 
  鏈?zhǔn)秸{(diào)用 
  一個(gè)鏈子接一個(gè)鏈子  
*/
var arr = [1,2,3];
var num = arr.map(function (items) {
  return items+1;
}).reduce(function (a,b) {//[2,3,4].reduce()
  return a+b;
})
​
console.log(num);//0 --- 2+3+4 = 9