php中 count---获取数组长度
js 中 arr.length 返回数组中元素数目
var obj = {name : 'lisi' , age : 29 , area : 'beijing'};
for (var k in obj) {
console.log(k + '~' + obj[k]);
var k in obj 遍历数组
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd"> <html xmlns="http://www.w3.org/1999/xhtml"> <head> <title>新建网页</title> <meta http-equiv="Content-Type" content="text/html; charset=utf-8" /> <meta name="description" content="布尔教育 http://www.itbool.com" /> </head> <body> <script> var arr = ['赵' ,'钱' , '孙' , '李' ]; for (var i = 0 ; i < arr.length ; i++) { console.log(arr[i]); }; var obj = {name : 'lisi' , age : 29 , area : 'beijing'}; for (var k in obj) { console.log(k + '~' + obj[k]); }; </script> </body> </html>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd"> <html xmlns="http://www.w3.org/1999/xhtml"> <head> <title>新建网页</title> <meta http-equiv="Content-Type" content="text/html; charset=utf-8" /> <meta name="description" content="布尔教育 http://www.itbool.com" /> </head> <body> <script> var arr = ['赵' ,'钱' , '孙' , '李' ]; for (var i = 0 ; i < arr.length ; i++) { console.log(arr[i]); }; var obj = {name : 'lisi' , age : 29 , area : 'beijing'}; for (var k in obj) { console.log(k + '~' + obj['k']); }; </script> </body> </html>

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