forEach() : 对数组进行遍历循环，对数组中的每一项运行给定函数。
格式： arr.forEach(function(value,index){})
<!DOCTYPE html> <html lang="en"> <head> <meta charset="UTF-8"> <meta name="viewport" content="width=device-width, initial-scale=1.0"> <meta http-equiv="X-UA-Compatible" content="ie=edge"> <title>Document</title> </head> <body> <script> var arr = [1, 3, 5, 7, 9, 11,'哈哈']; arr.forEach(function (value, index) { console.log(index + ':' + value); }) </script> </body> </html>
