< FORM>如果没有选择复选框，提醒！ ..提交。 （Javascript） [英] <FORM> If no checkbox is selected, alert! .. ELSE .. submit. (Javascript)

问题描述

语言： Javascript

我真的很讨厌提出这样一个看似简单的问题，但看起来很简单，这个工作。

我试图完全用单独的JavaScript（没有库支持）。

我有一个带有复选框的表单...

所有复选框都命名为 files [] ，因为我使用结果数组：

 < input type ='checkbox' name ='file []'id ='1'value ='1'/>文件1< br> 
< input type ='checkbox'name ='files []'id ='2'value ='2'/>文件2< br> 
< input type ='checkbox'name ='files []'id ='3'value ='3'/>文件3< br> 
  

我想要做的是，当用户提交 如果未选中复选框，请返回 ALERT！。 li>

ELSE 请提交表单

/ strong>：

 < form name =deleteFiles action =method =postonsubmit =return confirm_update（）;> 
 
< input type ='checkbox'name ='files []'id ='1'value ='1'/>文件1< br> 
< input type ='checkbox'name ='files []'id ='2'value ='2'/>文件2< br> 
< input type ='checkbox'name ='files []'id ='3'value ='3'/>文件3< br> 
< input type =submitvalue =Submitname =submit> 
 
< / form> 
  

代码：：

 function confirm_update 
 var aCheckbox = document.deleteFiles.getElementsByTagName（'input'）; 
 
 if（aCheckbox.checked）{
 return confirm（您确定要继续删除所选文件吗？ 
 
} else {
 alert（您没有要删除的任何选定文件。 
 return false; 
} 
} 
  

在操作中： http://jsfiddle.net/DVqwB/3/

显然，它不工作，我知道我应该使用 getElementsById ，但因为他们都有唯一的ID，我不能使用。我也知道在这个网站有很多解决方案，但如果你看 - 他们实际上使用jQuery ...

任何帮助&指导将非常感谢！非常感谢。

解决方案

迭代集合的正确方法是：（full example）

  function confirm_update（）{var arrCheckboxes = document.deleteFiles.elements [files []]; var checkCount = 0; for（var i = 0; i  

  body {margin：30px;}  

 < form name =deleteFilesaction =method = postonsubmit =return confirm_update（）;> < input type ='checkbox'name ='files []'id ='1'value ='1'/>文件1< br /> < input type ='checkbox'name ='files []'id ='2'value ='2'/>文件2< br /> < input type ='checkbox'name ='files []'id ='3'value ='3'/>文件3< br /> < input type =submitvalue =Submitname =submit/> < / form>  

Language: Javascript

I really hate to ask such a seemingly simple question, but simple as it seems, I can't get this to work.

I am trying to do this entirely with pure Javascript alone (no library support).

I have a form with checkboxes...
All checkboxes are named files[] because I use the results in an array:

<input type='checkbox' name='files[]' id='1' value='1' /> file 1<br>
<input type='checkbox' name='files[]' id='2' value='2' /> file 2<br>
<input type='checkbox' name='files[]' id='3' value='3' /> file 3<br>

What I'm trying to do is, when the user submits the form:

• IF no checkbox is checked >> return ALERT!
• ELSE submit the form

Here's my form:

<form name="deleteFiles" action="" method="post" onsubmit="return confirm_update();">

    <input type='checkbox' name='files[]' id='1' value='1' /> file 1<br>
    <input type='checkbox' name='files[]' id='2' value='2' /> file 2<br>
    <input type='checkbox' name='files[]' id='3' value='3' /> file 3<br>
    <input type="submit" value="Submit" name="submit">

</form>​

And here's my Javascript code:

function confirm_update() {
    var aCheckbox = document.deleteFiles.getElementsByTagName('input');

    if (aCheckbox.checked){
    return confirm("Are you sure you want to proceed deleting the selected files?");

    } else {
        alert("You do not have any selected files to delete.");
        return false;
    }
}​

In action: http://jsfiddle.net/DVqwB/3/

Apparently, it is not working, I know I should use getElementsById but since they each have unique IDs I can't use that. And I also know that there are lots of solutions on this site, but if you look - they actually use jQuery...

Any help & guidance would be greatly appreciated! Thank you so much.

解决方案

Correct way to iterate the collection will be: (full example)

function confirm_update() {
    var arrCheckboxes = document.deleteFiles.elements["files[]"];
    var checkCount = 0;
    for (var i = 0; i < arrCheckboxes.length; i++) {
        checkCount += (arrCheckboxes[i].checked) ? 1 : 0;
    }

    if (checkCount > 0){
        return confirm("Are you sure you want to proceed deleting the selected   files?");
    } else {
        alert("You do not have any selected files to delete.");
        return false;
    }
}

body {
    margin: 30px;
}

<form name="deleteFiles" action="" method="post" onsubmit="return confirm_update();">
    
    <input type='checkbox' name='files[]' id='1' value='1' /> file 1<br />
    <input type='checkbox' name='files[]' id='2' value='2' /> file 2<br />
    <input type='checkbox' name='files[]' id='3' value='3' /> file 3<br />
    <input type="submit" value="Submit" name="submit" />
    
</form>

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