为什么javaweb中的表单提交效果失效

在eclipse的jsp界面中form表单的onsubmit用不了，而在Hbuilder中的HTML界面却可以用，这是什么原因

            <form action="/ljp/RegisterServlet" method="post" id="myRegisterForm" onsubmit ="return check()">
                <img src="img/icon/user.png"/>
                <input type="text" name="userName" id="RuserName" maxlength="20" placeholder="Username or Mob" 
                autocomplete="off" onblur="checkUserName()" onkeyup="checkUserName()"/><br/>
                <span id="userNameJudge">请输入3-8字符</span><br/>
                <img src="img/icon/tel.png"/>
                <input type="tel" name="telNum" id="telNum" maxlength="20" placeholder="Telephone Number" 
                autocomplete="off" onblur="checkTelNum()" onkeyup="checkTelNum()"/><br/>
                <span id="telNumJudge">请输入您的手机号码</span><br/>
                <img src="img/icon/sex.png"/>
                <input type="radio" name="sex" class="sex" value="男"/><b>男</b>
                <input type="radio" name="sex" class="sex" value="女"/><b>女</b><br/>
                <img src="img/icon/pwd.png"/>
                <input type="password" name="userPwd" id="RuserPwd" maxlength="20" placeholder="Password" autocomplete="off"
                 onblur="hidden1();checkUserPwd()" onkeyup="checkUserPwd()"/><img id="reye" src="img/icon/eye.png"/><br/>
                <span id="userPwdJudge">请输入6-16位密码</span><br/>
                <img src="img/icon/pwd.png"/>
                <input type="password" name="userPwd1" id="RuserPwd1" maxlength="20" placeholder="Password Again" autocomplete="off"
                onblur="hidden2();checkUserPwd1()" onkeyup="checkUserPwd1()"/><img id="reye1" src="img/icon/eye.png"/><br/>
                <span id="userPwd1Judge">请再次确认密码</span><br/>
                <input type="submit" value="Sign Up" id="register"/>
            </form>

function check(){
    if(checkFlag()&&checkTelNum()&&checkUserPwd()&&checkUserPwd1()){
        alert("恭喜你，注册成功！");
        return true;}
    else{
        alert("注册信息错误，请进行修改");
    return false;}
}