JavaScript 倒计时 （由实现数据库时时更新 引出的 ）
<!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"><head><meta http-equiv="Content-Type" content="text/html; charset=utf-8" /><title>倒计10秒再提交</title><script language="JavaScript"> var i=10; function change(){var btn=document.getElementById("button");i--;if(i != 0){btn.value="Agree "+i;}else{btn.value="Agree";}if(i==0){ btn.disabled=false; ?}else{setTimeout("change()",1000);}}</script></head><body onload="change()"><form method="post" id="form1"> <input type='submit' id="button" disabled="disabled" value="Agree"> </form></body></html> ??