1

当用户按下提交时，我无法让它调用下面的 JS，我错过了什么

<script type="text/javascript"> 

        function required(){  
            if (document.getElementById("Username").value.length == 0)  
            {   
                alert("message");        
                return false;   
            }       
            return true;   
        }

    </script>

用户输入用户名的代码

<h:form> <!--onsubmit="return username_validation();">-->


                <h:outputLabel for="username">Please enter your username: </h:outputLabel>
                <h:inputText id="Username" label="Username" value="#{user.id}"
                             size="20" required="true" requiredMessage="Please enter a username" >
                    <f:ajax event="blur" render="usernameMessage" />
                </h:inputText><br></br><br></br>
                <h:message id="usernameMessage" for="username" />
                To print a piece of text, please press the submit button below to upload the text:<br/><br/>
                <h:commandButton type="Submit" value="Submit" onclick="return username_validation()" action="upload/uploadText" styleClass="submit"/>

            </h:form>

多亏了你们的帮助，我现在有了以下信息：但是我永远无法得到错误消息旁边的我该h:inputText怎么做？

 <h:form> <!--onsubmit="return username_validation();">-->


                    <h:outputLabel for="username">Please enter your username: </h:outputLabel>
                    <h:inputText id="Username" label="Username" value="#{user.id}"
                                 size="20" required="true" requiredMessage="Please enter a username" >

                    </h:inputText><br></br><br></br>

                    To print a piece of text, please press the submit button below to upload the text:<br/><br/>
                    <h:commandButton type="Submit" value="Submit" onclick="return username_validation()" action="upload/uploadText" styleClass="submit"/>

                </h:form>

这也是我的 userBean，我添加了 @NotNull 但这目前不起作用，我错过了什么吗？

package com.corejsf;

import java.io.Serializable;
import javax.inject.Named;
import javax.enterprise.context.SessionScoped;
import javax.validation.constraints.NotNull;


@Named("user")
@SessionScoped
public class UserBean implements Serializable {

    @NotNull(message = "Please enter a username")
    private String id;

    public String getId() {
        return id;
    }

    public void setId(String newValue) {
        id = newValue;
    }
    private String fileText;

    public String getFileText() {
        return fileText;
    }

    public void setFileText(String fileText) {
        this.fileText = fileText;
    }
}
4

1 回答 1

3

查看生成的 HTML 源代码。在浏览器中右键单击页面并执行View Source。UsernameHTML 源代码中根本不存在具有 ID 的元素。相应地修复它。

<h:form id="form" ...>
    <h:inputText id="username" ... />
    ...
</h:form>

和

var usernameElement = document.getElementById("form:username");

与具体问题无关，纯粹通过 JavaScript 执行验证的方向是错误的。这是不可靠的。只需使用required="true".

<h:form>
    <h:inputText id="username" ... required="true">
        <f:ajax event="blur" render="usernameMessage" />
    </h:inputText>
    <h:message id="usernameMessage" for="username" />
    ...
</h:form>

也可以看看：

于 2012-12-24T23:10:43.610 回答