<form action="MemberServlet" method="post" onsubmit="return validate(this);">
function validate(form){ if(form.name.value.trim() == ""){ alert("您必须输入姓名"); return false; } if(form.nickname.value.trim() == ""){ alert("您必须输入昵称"); return false; } if(form.password.value.trim() == ""){ alert("您必须输入密码"); return false; } return true; }