ES5中的常用的数组方法

1. isArray方法
   检验变量是否包含数组数据
   var months = ['January', 'Febraury', 'March', 'April', 'May'];
   alert(Array.isArray(months)); //true
2. forEach方法
   var months = ['January', 'Febraury', 'March', 'April', 'May'];
   months.forEach(function(value, index, fullArray){
   alert(value + ' is month number ' + (index+1) + ' of ' + fullArray.length);
   }); //循环遍历数组 第一个参数是数组值，第二个是索引，第三个是当前数组。（下面的参数同样如此）
3. every和some方法
   //every方法遍历数组每一个元素，将每一个元素和一个条件比较，都满足返回true,否则为false.
   var months = ['January', 'Febraury', 'March', 'April', 'May'];
   var every = months.every(function(value, index, fullArray){
   return value.indexOf('r') >= 0;
   });
   alert(every); //false
   //some也是遍历数组，但只要任意一个满足条件就返回true，否则为false
   var months = ['January', 'Febraury', 'March', 'April', 'May'];
   var some = months.some(function(value, index, fullArray){
   return value.indexOf('r') >= 0;
   });
   alert(some); //true
4. map方法
   //返回一个处理后的数组,原数组保持不变
   var months = ['January', 'Febraury', 'March', 'April', 'May'];
   months.map(function(value, index, fullArray){
   return value + ' is month number ' + (index+1) + ' of ' + fullArray.length;
   }); // ["January is month number 1 of 5", "Febraury is month number 2 of 5", "March is month number 3 of 5", "April is month number 4 of 5", "May is month number 5 of 5"]
5. filter方法
   var months = ['January', 'Febraury', 'March', 'April', 'May'];
   var filterMonths = months.filter(function(value, index, fullArray){
   return value.indexOf('r') >= 0;
   });
   console.log(filterMonths); // ["January", "Febraury", "March", "April"]