按钮提交倒计时实现

var secs = 9;var wait = secs * 1000;/*其中licenseform为提交表单即<form name="licenseform">...</form>，  其中btnSubmit为按钮submit的name值即<input type="button" name="btnSubmit"/>*/document.licenseform.btnSubmit.value = "我同意 [" + secs + "]";document.licenseform.btnSubmit.disabled = true;for(i = 1; i <= secs; i++){window.setTimeout("Update(" + i + ")", i * 1000);}//window.setTimeout("Timer()", wait);function Update(num){if(num != secs){printnr = (wait / 1000) - num;document.licenseform.btnSubmit.value = "我同意 [" + printnr + "]";}}function Timer(){document.licenseform.btnSubmit.disabled = false;document.licenseform.btnSubmit.value = " 我同意 ";}