function CheckForm(form){
if (form.admin.value==""){
alert('请输入用户名')
form.admin.focus();
return false;
}
if (form.password.value==""){
alert('请输入密码')
form.password.focus();
return false;
}
if (form.VerifyCode.value==""){
alert('请输入验证码')
form.VerifyCode.focus();
return false;
}
}