当给出一个表格`
var arr=[
{id:1001,name:"苹果IphoneX",price:6900,num:2,info:"最新的苹果手机"},{id:1002,name:"小米10",price:3900,num:3,info:"最新的小米手机"},{id:1003,name:"华为meta10",price:8900,num:4,info:"最新的华为手机"},{id:1004,name:"锤子手机",price:1900,num:1,info:"最新的锤子手机"},{id:1005,name:"三星手机",price:4900,num:2,info:"最新的三星手机"},{id:1006,name:"vivo手机",price:2900,num:4,info:"最新的vivo手机"},{id:1007,name:"魅族手机",price:1900,num:5,info:"最新的魅族手机"},];
咱们须要把数组中的内容输入到表格里，且表格里该当有表头，表头信息是对象中的属性名，也就是咱们常说的key，这就须要遍历数组而后输入内容在表格中，这个时候咱们该当首先把表头信息输入，这时须要遍历属性名，而后依照程序输入。这里应用for···in办法进行
for(var key in arr[j]){ document.write("<td>"+key+"</td>"); }而后对数组每个对象进行遍历，将属性名对应的属性值输入到表格对应地位。
<!DOCTYPE html><html lang="en"><head> <meta charset="UTF-8"> <meta name="viewport" content="width=device-width, initial-scale=1.0"> <title>Document</title> <style> table { border-collapse: collapse; width: 800px; } td,th{ height: 30px; line-height: 30px; text-align: center; font-size: 18px; border: 1px solid #000000; } </style></head><body> <script> var arr=[ {id:1001,name:"苹果IphoneX",price:6900,num:2,info:"最新的苹果手机"}, {id:1002,name:"小米10",price:3900,num:3,info:"最新的小米手机"}, {id:1003,name:"华为meta10",price:8900,num:4,info:"最新的华为手机"}, {id:1004,name:"锤子手机",price:1900,num:1,info:"最新的锤子手机"}, {id:1005,name:"三星手机",price:4900,num:2,info:"最新的三星手机"}, {id:1006,name:"vivo手机",price:2900,num:4,info:"最新的vivo手机"}, {id:1007,name:"魅族手机",price:1900,num:5,info:"最新的魅族手机"},]; var i=0,j=0; document.write("<table>"); j=0; for(i=0;i<arr.length;i++){ if(i===0){ document.write("<tr>"); for(var key in arr[j]){ document.write("<td>"+key+"</td>"); } document.write("</tr>"); } else { document.write("<tr>"); for(let key in arr[j]){ document.write("<td>"+arr[j][key]+"</td>"); } document.write("</tr>"); j=j+1; } } document.write("</table>"); </script></body></html>