RUNOOB.COM
源代码：
点击运行
<!DOCTYPE html> <html> <head> <meta charset="utf-8"> <title>电脑学习网教程(runoob.com)</title> <script> var c=0; var t; var timer_is_on=0; function timedCount(){ document.getElementById('txt').value=c; c=c+1; t=setTimeout("timedCount()",1000); } function doTimer(){ if (!timer_is_on) { timer_is_on=1; timedCount(); } } </script> </head> <body> <form> <input type="button" value="开始计数!" onClick="doTimer()"> <input type="text" id="txt"> </form> <p>单击按钮，输入框将从0开始一直计数。</p> </body> </html>
运行结果