代码如下：
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd"> <html xmlns="http://www.w3.org/1999/xhtml" xml:lang="en"> <head> <meta http-equiv="Content-Type" content="text/html;charset=UTF-8"> <title>Document</title> <style> *{margin: 0px;padding: 0px;} body{padding: 100px;} input{padding: 5px 15px;} </style> <script> window.onload=function(){ var oBtn = document.getElementsByTagName('input')[0]; var i=0; oBtn.onclick=function(){ this.value=++i; alert(i); } } </script> </head> <body> <input type="button" value="0"/> </body> </html>
结果如下图所示：
