一，效果图。
二，代码。
<!DOCTYPE html>
<html> <head> <meta charset="utf-8"> <title>javascript for循环</title> </head> <body> <script> cars = ["bmw", "volvo", "saab", "ford"]; for (var i = 0; i < cars.length; i++) { document.write(cars[i] + "<br>"); } </script> <p>点击按钮循环代码5次</p> <button onclick="myFunction()">点击这里</button> <p id="demo"></p> <script> function myFunction() { var x = ""; for (var i = 0; i < 5; i++) { x = x + "the number is" + i + "<br>"; } document.getElementById("demo").innerHTML = x; } </script> <p>点击下面的按钮，循环遍历对象"person"的属性</p> <button onclick="myFunction()">点击这里</button> <p id="demo1"></p> <script> function myFunction() { var x; var txt = ""; var person = { fname: "bill", lname: "gates", age: 56 }; for (x in person) { txt = txt + person[x]; } document.getElementById("demo1").innerHTML = txt; } </script> </body> </html>
参考资料：《菜鸟教程》
一，效果图。
二，代码。
<!DOCTYPE html>
<html> <head> <meta charset="utf-8"> <title>javascript for循环</title> </head> <body> <script> cars = ["bmw", "volvo", "saab", "ford"]; for (var i = 0; i < cars.length; i++) { document.write(cars[i] + "<br>"); } </script> <p>点击按钮循环代码5次</p> <button onclick="myFunction()">点击这里</button> <p id="demo"></p> <script> function myFunction() { var x = ""; for (var i = 0; i < 5; i++) { x = x + "the number is" + i + "<br>"; } document.getElementById("demo").innerHTML = x; } </script> <p>点击下面的按钮，循环遍历对象"person"的属性</p> <button onclick="myFunction()">点击这里</button> <p id="demo1"></p> <script> function myFunction() { var x; var txt = ""; var person = { fname: "bill", lname: "gates", age: 56 }; for (x in person) { txt = txt + person[x]; } document.getElementById("demo1").innerHTML = txt; } </script> </body> </html>
参考资料：《菜鸟教程》