javascript 如何自动检查所有具有相同名称的复选框？
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How to auto check all checkboxes with same name?
提问by rohit_mishra
I have used checkboxes for checking the mails in my mailing system which is developed in Java.
我使用复选框来检查我用 Java 开发的邮件系统中的邮件。
I want to check all the checkboxes on the click of upper checkbox, but the problem is there that checkboxes are displayed in the the loop according to number of mails retrieved.
我想在单击上方复选框时检查所有复选框，但问题是根据检索到的邮件数量在循环中显示复选框。
Please help me where should i put the javascript code to solve this problem.
请帮我把javascript代码放在哪里来解决这个问题。
The loop code of inbox is given below:
收件箱循环代码如下：
<tr >
<% for(int i=0;i<messageList.size();i++) { message = (Message)messageList.get(i);%>
<td width="10%" height="33" align="left" valign="top" bgcolor="#EEE" >
<!--This link display the full message-->
<input name="Mark_Mail" id="mark_mail" onclick="myfunction(this);" type="checkbox" value="<%=message.getMailId()%>" width="50" height="30" align="top" >
<span id="space1" style="padding:2px"></span>
<!--Check all the Checkboxes-->
<script type="text/javascript">
function checkAll()
{
document.getElementById('mark_mail').checked = "true";
}
</script>
<img src="Images/UnStarred.jpg" height="15" border="0" id="image1" onclick="swapImage()" />
<span id="space1" style="padding:2px"></span>
</td>
<td width="90%" height="33" align="left" colspan="7" valign="bottom" bgcolor="#EEE" >
<!--This link display the full message-->
<a id="link" href="viewMail.jsp?mailId=<%=message.getMailId()%>&isAttach=<%=message.getAttachmentFlag()%>">
<!--Display Sender Address-->
<font color="#000000" size="1"><strong><%=message.getSenderAddress()%></strong></font>
<span id="space1" style="padding:6px"></span>
<!--For Display Message Subject-->
<font color="#000000" size="1"><strong><%=message.getSubject()%></strong></font>
<span id="space1" style="padding:6px"></span>
<!--For Display Attachment Image-->
<%if(message.getAttachmentFlag().equals("1")){%><input type="hidden" name="filename" id="filename" value="<%=message.getFileName()%>" /><input type="hidden" name="filesize" id="filesize" value="<%=message.getFileSize()%> /><img src ="Images/attachment.jpg" style="bgcolor: #EEE" /><%}else{%><span style="padding-left:12px" ></span><%}%>
<span id="space1" style="padding:6px"></span>
<!--For Display Time and Date of messaging-->
<font color="#000000" size="1"><strong><%=message.getTimestamp()%><span style="padding-left:5px"></span><%=message.getDate()%><input type="hidden" name="label" value="<%=message.getLabel()%>"></strong></font>
</a></td>
</tr><% } %>
回答by Shadow Wizard is Ear For You
You need to get the elements by their name, as ID must be unique:
您需要按名称获取元素，因为 ID 必须是唯一的：
function checkAll() {
var arrMarkMail = document.getElementsByName("mark_mail");
for (var i = 0; i < arrMarkMail.length; i++) {
arrMarkMail[i].checked = true;
}
}
Just place this code in the <head>section of the page.
只需将此代码放在<head>页面的部分中即可。
To call it, have such checkbox wherever you like:
Master: <input type="checkbox" onclick="checkAll();" />
However this better be done by a button:
要调用它，在任何你喜欢的地方都有这样的复选框： 大师：<input type="checkbox" onclick="checkAll();" />
但是最好通过一个按钮来完成：
<button type="button" onclick="checkAll();">Check All</button>
