document.getElementById() 错误

发布于 2025-01-06 01:51:40 字数 6881 浏览 0 评论 0原文

我正在尝试编写一个 jdo 查询，其中我必须根据用户在 jsp 上选择的类别获取一组值...我的查询如下所示

Query query2 = pm.newQuery("select from " + ProductDB.class.getName()+ "where pCategory = " document.getElementById("cname").text);

现在在我的 jsp 页面上，我有一个动态下拉列表框和标签中我已将 id 标签指定为“cname”。因此，当我执行上述查询时，我希望它能够获取用户选择的类别。

但是我收到此错误：

令牌“文档”上的语法错误，删除此令牌

我的选择标签如下所示：

<select name = "cname" id="cname">
.
.
.
</select>

我在这里缺少什么？

更新：

我将 jsp 文件的完整代码放在下面：

<%@ page contentType="text/html;charset=UTF-8" language="java"%>
<%@ page import="java.util.*"%>
<%@ page import="javax.jdo.Query"%>
<%@ page import="javax.jdo.PersistenceManager"%>
<%@ page import="com.google.appengine.api.users.User"%>
<%@ page import="com.google.appengine.api.datastore.Key"%>
<%@ page import="com.google.appengine.api.users.UserService"%>
<%@ page import="com.google.appengine.api.users.UserServiceFactory"%>
<%@ page import="java.net.*"%>
<%@ page import="javax.servlet.http.HttpServletRequest"%>
<%@ page import="com.nerdy.needs.*"%>
<html>
<head>
<title>Product Inventory</title>
<META HTTP-EQUIV="Refresh" CONTENT="450">
<link rel="stylesheet" href="login.css" type="text/css" />
</head>
<h1 align="center">Product Inventory</h1>
<body>
<form>
<table>
    <tr>
        <td>View</td>
        <td><select name="cname" id="cname">
            <option value="all">All</option>
            <%
                PersistenceManager pm = PMF.get().getPersistenceManager();
                Query query = pm.newQuery("select cname from "
                        + CategoryDB.class.getName());
                List<String> categories = new ArrayList<String>();
                categories = (List<String>) query.execute();
                String[] c = categories.toArray(new String[categories.size()]);
                for (int i = 0; i < c.length; i++) {
                    String s = c[i];
            %>
            <option value="<%=s%>"><%=s%></option>
            <%
                }
            %>
        </select></td>
        <td>Products</td>
    </tr>
</table>
</form>
<%
    if (document.getElementById("cname").value == "all") {
        PersistenceManager pm1 = PMF.get().getPersistenceManager();
        Query query1 = pm1.newQuery("select * from "
                + ProductDB.class.getName());
        List<ProductDB> prods1 = (List<ProductDB>) query1.execute();
        if (prods1.isEmpty()) {
%>
<table class="items">
    <tr>
        <th class="main">Image</th>
        <th class="main">Category</th>
        <th class="main">Name</th>
        <th class="main">Price</th>
        <th class="main">Description</th>
    </tr>
    <tr class="lightBlue">
        <td class="actions" colspan=100%>
        <p>No items were found.</p>
        </td>
    </tr>
</table>
<%
    } else {
%>
<table class="topics">
    <tr>
        <th class="main">Image</th>
        <th class="main">Category</th>
        <th class="main">Name</th>
        <th class="main">Price</th>
        <th class="main">Description</th>
    </tr>
    <%
        for (ProductDB p : prods1) {
    %>
    <tr>
        <td>
        <p><b> <img width="100" height="100"
            src="http://localhost:8888/serve?id= <%=p.getProductImage()%>">
        </b></p>
        </td>
        <td>
        <p><b><%=p.getProductCategory()%></b></p>
        </td>
        <td>
        <p><b><%=p.getProductName()%></b></p>
        </td>
        <td>
        <p><b><%=p.getProductPrice()%></b></p>
        </td>
        <td>
        <p><b><%=p.getProductDescription()%></b></p>
        </td>
    </tr>
    <%
        }
    %>
</table>
<%
    pm1.close();
        }
    } else {
        PersistenceManager pm2 = PMF.get().getPersistenceManager();
        Query query2 = pm.newQuery("select * from "
                + ProductDB.class.getName() + "where pCategory = "
                + document.getElementById("cname").value);
        List<ProductDB> prods2 = (List<ProductDB>) query2.execute();
        if (prods2.isEmpty()) {
%>
<table class="items">
    <tr>
        <th class="main">Image</th>
        <th class="main">Category</th>
        <th class="main">Name</th>
        <th class="main">Price</th>
        <th class="main">Description</th>
    </tr>
    <tr class="lightBlue">
        <td class="actions" colspan=100%>
        <p>No items were found.</p>
        </td>
    </tr>
</table>
<%
    } else {
%>
<table class="topics">
    <tr>
        <th class="main">Image</th>
        <th class="main">Category</th>
        <th class="main">Name</th>
        <th class="main">Price</th>
        <th class="main">Description</th>
    </tr>
    <%
        for (ProductDB p : prods2) {
    %>
    <tr>
        <td>
        <p><b> <img width="100" height="100"
            src="http://localhost:8888/serve?id= %=p.getProductImage()%>">
        </b></p>
        </td>
        <td>
        <p><b><%=p.getProductCategory()%></b></p>
        </td>
        <td>
        <p><b><%=p.getProductName()%></b></p>
        </td>
        <td>
        <p><b><%=p.getProductPrice()%></b></p>
        </td>
        <td>
        <p><b><%=p.getProductDescription()%></b></p>
        </td>
    </tr>
    <%
        }
    %>
</table>
<%
    pm2.close();
        }
    }
%>
</body>
</html>

我在两个地方收到“文档无法解析”错误 - 一个在 if 语句

if(document.getElementById("cname").value=="all")

，另一个在查询语句

Query query2 = pm.newQuery("select * from " + ProductDB.class.getName()+ "where pCategory = " + document.getElementById("cname").value);

任何人都可以帮忙我要弄清楚出了什么问题？

原文

I am trying to write a jdo query in which I have to get a set of values based on the category that the user selects on the jsp...my query looks like this

Query query2 = pm.newQuery("select from " + ProductDB.class.getName()+ "where pCategory = " document.getElementById("cname").text);

Now on my jsp page, I have a dynamic drop-down box and in the tag I have given the id tag as "cname". So when I execute the above query I am hoping it will get the category that the user selects.

However I am getting this error:

Syntax error on token "document", delete this token

My select tag looks like this :

<select name = "cname" id="cname">
.
.
.
</select>

What am i missing here?

UPDATE :

I am putting my entire code for the jsp file below :

<%@ page contentType="text/html;charset=UTF-8" language="java"%>
<%@ page import="java.util.*"%>
<%@ page import="javax.jdo.Query"%>
<%@ page import="javax.jdo.PersistenceManager"%>
<%@ page import="com.google.appengine.api.users.User"%>
<%@ page import="com.google.appengine.api.datastore.Key"%>
<%@ page import="com.google.appengine.api.users.UserService"%>
<%@ page import="com.google.appengine.api.users.UserServiceFactory"%>
<%@ page import="java.net.*"%>
<%@ page import="javax.servlet.http.HttpServletRequest"%>
<%@ page import="com.nerdy.needs.*"%>
<html>
<head>
<title>Product Inventory</title>
<META HTTP-EQUIV="Refresh" CONTENT="450">
<link rel="stylesheet" href="login.css" type="text/css" />
</head>
<h1 align="center">Product Inventory</h1>
<body>
<form>
<table>
    <tr>
        <td>View</td>
        <td><select name="cname" id="cname">
            <option value="all">All</option>
            <%
                PersistenceManager pm = PMF.get().getPersistenceManager();
                Query query = pm.newQuery("select cname from "
                        + CategoryDB.class.getName());
                List<String> categories = new ArrayList<String>();
                categories = (List<String>) query.execute();
                String[] c = categories.toArray(new String[categories.size()]);
                for (int i = 0; i < c.length; i++) {
                    String s = c[i];
            %>
            <option value="<%=s%>"><%=s%></option>
            <%
                }
            %>
        </select></td>
        <td>Products</td>
    </tr>
</table>
</form>
<%
    if (document.getElementById("cname").value == "all") {
        PersistenceManager pm1 = PMF.get().getPersistenceManager();
        Query query1 = pm1.newQuery("select * from "
                + ProductDB.class.getName());
        List<ProductDB> prods1 = (List<ProductDB>) query1.execute();
        if (prods1.isEmpty()) {
%>
<table class="items">
    <tr>
        <th class="main">Image</th>
        <th class="main">Category</th>
        <th class="main">Name</th>
        <th class="main">Price</th>
        <th class="main">Description</th>
    </tr>
    <tr class="lightBlue">
        <td class="actions" colspan=100%>
        <p>No items were found.</p>
        </td>
    </tr>
</table>
<%
    } else {
%>
<table class="topics">
    <tr>
        <th class="main">Image</th>
        <th class="main">Category</th>
        <th class="main">Name</th>
        <th class="main">Price</th>
        <th class="main">Description</th>
    </tr>
    <%
        for (ProductDB p : prods1) {
    %>
    <tr>
        <td>
        <p><b> <img width="100" height="100"
            src="http://localhost:8888/serve?id= <%=p.getProductImage()%>">
        </b></p>
        </td>
        <td>
        <p><b><%=p.getProductCategory()%></b></p>
        </td>
        <td>
        <p><b><%=p.getProductName()%></b></p>
        </td>
        <td>
        <p><b><%=p.getProductPrice()%></b></p>
        </td>
        <td>
        <p><b><%=p.getProductDescription()%></b></p>
        </td>
    </tr>
    <%
        }
    %>
</table>
<%
    pm1.close();
        }
    } else {
        PersistenceManager pm2 = PMF.get().getPersistenceManager();
        Query query2 = pm.newQuery("select * from "
                + ProductDB.class.getName() + "where pCategory = "
                + document.getElementById("cname").value);
        List<ProductDB> prods2 = (List<ProductDB>) query2.execute();
        if (prods2.isEmpty()) {
%>
<table class="items">
    <tr>
        <th class="main">Image</th>
        <th class="main">Category</th>
        <th class="main">Name</th>
        <th class="main">Price</th>
        <th class="main">Description</th>
    </tr>
    <tr class="lightBlue">
        <td class="actions" colspan=100%>
        <p>No items were found.</p>
        </td>
    </tr>
</table>
<%
    } else {
%>
<table class="topics">
    <tr>
        <th class="main">Image</th>
        <th class="main">Category</th>
        <th class="main">Name</th>
        <th class="main">Price</th>
        <th class="main">Description</th>
    </tr>
    <%
        for (ProductDB p : prods2) {
    %>
    <tr>
        <td>
        <p><b> <img width="100" height="100"
            src="http://localhost:8888/serve?id= %=p.getProductImage()%>">
        </b></p>
        </td>
        <td>
        <p><b><%=p.getProductCategory()%></b></p>
        </td>
        <td>
        <p><b><%=p.getProductName()%></b></p>
        </td>
        <td>
        <p><b><%=p.getProductPrice()%></b></p>
        </td>
        <td>
        <p><b><%=p.getProductDescription()%></b></p>
        </td>
    </tr>
    <%
        }
    %>
</table>
<%
    pm2.close();
        }
    }
%>
</body>
</html>

I am getting "document cannot be resolved" errors in two places - one at the if statement

if(document.getElementById("cname").value=="all")

and the other at the query statement

Query query2 = pm.newQuery("select * from " + ProductDB.class.getName()+ "where pCategory = " + document.getElementById("cname").value);

Can anyone help me to figure out what is wrong?

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卸妝后依然美 2025-01-13 01:51:40

您的具体问题是您将 Java/JSP 与 JavaScript 混合在一起。您似乎期望它们同步运行，并且您似乎期望 JavaScript 的 document 对象变量也存在于 JSP scriptlet 代码中。

这是错误的。 Java/JSP 是一个 HTML 代码生成器。它根据 HTTP 请求在 Web 服务器中运行，生成 HTML/JS 代码并将其作为 HTTP 响应发送回 Web 浏览器。所有 Web 浏览器检索的都是纯 HTML/JS 代码。右键单击网络浏览器中的页面，然后执行查看源代码来亲自查看。

提交的值

<select name="cname">

您的具体功能需求似乎是您需要获取Java/JSP端

。您需要通过HttpServletRequest#getParameter()将其作为请求参数获取。因此，替换

<%
    if (document.getElementById("cname").value == "all") {
        // ...
    }
%>

为

<%
    if ("all".equals(request.getParameter("cname"))) {
        // ...
    }
%>

也就是说，在 JSP 文件中编写 Java 代码是一个糟糕的事情练习。也在这方面努力。请注意，此问题与 JDO无关。

Your concrete problem is that you're mixing Java/JSP with JavaScript. You seem to expect that they run in sync and you seem to expect that JavaScript's document object variable is also present in JSP scriptlet code.

This is wrong. Java/JSP is a HTML code generator. It runs in webserver upon a HTTP request and generates HTML/JS code and sends it back to webbrowser as HTTP response. All the webbrowser retrieves is plain HTML/JS code. Rightclick the page in webbrowser and do View Source to see it yourself.

Your concrete functional requirement seems to be that you need to grab the the submitted value of

<select name="cname">

in the Java/JSP side.

You need to get it as a request parameter by HttpServletRequest#getParameter(). So, replace

<%
    if (document.getElementById("cname").value == "all") {
        // ...
    }
%>

<%
    if ("all".equals(request.getParameter("cname"))) {
        // ...
    }
%>

That said, writing Java code in JSP files is a poor practice. Work on that as well. Note that this problem is unrelated to JDO.

回复收藏 0 原文

小女人ら 2025-01-13 01:51:40

您忘记了 document.getElementById 之前的加号。

正确的代码是

Query query2 = pm.newQuery("select from " + ProductDB.class.getName() + "where pCategory = " + document.getElementById("cname").text);

另外，虽然这会修复语法错误，但代码仍然无法工作。根据 W3C DOM 规范，

You forgot the plus mark before the document.getElementById.

The correct code would be

Query query2 = pm.newQuery("select from " + ProductDB.class.getName() + "where pCategory = " + document.getElementById("cname").text);

Also, although that will fix the syntax error, the code still won't work. According to W3C DOM specification, the <select/> element doesn't have the text attribute; you should use the value, or selectedIndex in conjunction with options instead.

回复收藏 0 原文

在你怀里撒娇 2025-01-13 01:51:40

尝试这种方式：-

var i = document.getElementById("cname").selectedIndex;

document.getElementById("cname").options[i].text;

或

document.getElementById("cname").value

更新：

列名也丢失了。它应该是* 或特定列名称。

Query query2 = pm.newQuery("select * from " + ProductDB.class.getName()+ "where pCategory = " + document.getElementById("cname").value);

根据您的错误更新，

您的代码应如下所示：-

if(document.getElementById("cname").value=="all") 
{ 
 <%
 PersistenceManager pm1 = PMF.get().getPersistenceManager(); 
 Query query1 = pm1.newQuery("select * from " + ProductDB.class.getName()); 
 List<ProductDB> prods1 = (List<ProductDB>) query1.execute(); 
%>
}

JSP 标签应在标签 <% 和 %> 之间声明，其他 html 标签应在外部。

根据您的代码：

问题是在 JSP 标记内部调用 document.getElementById("cname").value 。那是错误的。

在这里，您可以将 cname 值作为查询字符串传递，并通过参数获取值
或者
将 document.getElementById("cname").value 值分配给 JSP 变量并对其进行处理。

Try this way:-

var i = document.getElementById("cname").selectedIndex;

document.getElementById("cname").options[i].text;

document.getElementById("cname").value

UPDATE:

Column names are missing too. It should be either * or specific column names.

Query query2 = pm.newQuery("select * from " + ProductDB.class.getName()+ "where pCategory = " + document.getElementById("cname").value);

As per your error update

your code should be as follows:-

if(document.getElementById("cname").value=="all") 
{ 
 <%
 PersistenceManager pm1 = PMF.get().getPersistenceManager(); 
 Query query1 = pm1.newQuery("select * from " + ProductDB.class.getName()); 
 List<ProductDB> prods1 = (List<ProductDB>) query1.execute(); 
%>
}

JSP tags should be declared between tags <% and %> and other html tags should be outside.

As per your Code:

The problem is document.getElementById("cname").value calling inside the JSP tags. That is wrong.

Here either you can pass cname value as query string and get value through the parameter
OR
Assign document.getElementById("cname").value value to JSP variable and process it.

回复收藏 0 原文

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