如何检查具有布尔值的复选框

Question

So the HTML spec says that you should add a checked attribute to the <input type="checkbox"> tag to mark it as checked. 因此，HTML规范要求您应将一个checked属性添加到<input type="checkbox">标记中，以将其标记为选中状态。 But I only have a boolean true or false value. 但是我只有一个布尔值true或false 。

As by design, I can't add any logic to the boolean value before it get parsed to html :(. Is it possible to check a Checkbox with a Boolean value on load just with html or js? I tried the following, but the onload seem not to trigger: 按照设计，我无法在布尔值解析为html之前添加任何逻辑：(。是否可以仅使用html或js检查加载时具有布尔值的Checkbox？我尝试了以下操作，但是onload似乎不会触发：

<input type="checkbox" onload="javascript:this.checked=true" />

I know that I can do something like this in jQuery: 我知道我可以在jQuery中执行以下操作：

$("[checked='false']").prop('checked',false)

I am looking for an elegant way to solve it. 我正在寻找一种解决问题的优雅方法。 This must parse the whole DOM-Tree and would slow down my page. 这必须解析整个DOM-Tree，并且会减慢我的页面的速度。

Edit (trying to explain): 编辑（试图解释）：

In my company there exist a application that does the following by design: 在我的公司中，有一个应用程序按设计执行以下操作：

 <input type="checkbox" checked="%IsValide%" >

The Server than automatically replaces the %IsValide% var with a database value. 然后，服务器会自动用数据库值替换%IsValide% var。 Here true or false. 这里是对还是错。 But then the checkbox is always checked, even if the value is false. 但是，即使该值为false，也始终选中该复选框。 I am aware that this is because of the design of html5: checked="true" and checked="false" will marke the checkbox always as checked. 我知道这是由于html5的设计引起的：checked =“ true”和checked =“ false”会将复选框始终标记为已选中。

Now I'am searching for a solution to use the true or false value from %IsValide% to check the box correctly with javascript (or even better, with html.). 现在，我正在寻找一种解决方案，以使用%IsValide%的true或false值来使用javascript（或什至更好的是使用html）正确选中该框。 I can use the %IsValide% at any position in the html tag. 我可以在html标记的任何位置使用%IsValide% 。 For example: 例如：

<input type="checkbox" onload="javascript:this.checked=%IsValide%" />

But I can not add logic before it get parsed to HTML like this: 但是我无法在将其解析为HTML之前添加逻辑，如下所示：

if(%IsValide%) {
 %IsValide%="checked";
}
else {
 %IsValide%="";
}

Answer 1

I'm trying to understand what your asking. 我想了解您的要求。 I'm thinking that you could accomplish it with some simple javascript: 我认为您可以使用一些简单的javascript完成它：

document.getElementById("yourCheckBoxId").checked = false; //this case it sets checked to false you can also do true

to check it on page load: 在页面加载时进行检查：

<body onload='document.getElementById("yourCheckBoxId").checked = true;'>

or avoid the onload attribute for body for checking it do this: 或避免body的onload属性进行检查：

<input type="checkbox" id="yourCheckBoxId" checked>

Then you just change it with javascript. 然后，您只需使用javascript进行更改即可。

My other guess is that your wanting to change the value of the checkbox? 我的另一个猜测是您要更改复选框的值吗？ Are you? 你是？ Post a comment below my answer saying that I didn't understand what you are asking. 在我的答案下方发表评论，说我不明白您的要求。 Hope this helps! 希望这可以帮助！ Here is my reference source: http://www.w3schools.com/jsref/prop_checkbox_checked.asp 这是我的参考来源： http : //www.w3schools.com/jsref/prop_checkbox_checked.asp

Answer 2

If your company's application sets checked="true" or checked="false" as you can see, this will not matter since checked is a boolean attribute and "the presence of this Boolean attribute indicates that the control is selected by default", and the checkbox will always be checked. 如您所见，如果您公司的应用程序设置了checked="true"或checked="false" ，那么这将无关紧要，因为checked是一个布尔属性，并且“此布尔属性的存在指示默认情况下该控件处于选中状态”，并且该复选框将始终处于选中状态。

This should fix it: 这应该解决它：

$('input[checked="false"]').prop('checked',false)

jsFiddle example jsFiddle示例

Answer 3

I think ultimately you're going about this the wrong way, but if I had no other option like you're saying, I think the best you'll end up with (performance wise) would be to add a class to your input (true or false) 我认为最终您会以错误的方式进行操作，但是，如果您没有像我所说的那样没有其他选择 ，那么我认为最终（在性能方面）最好的做法是在输入中添加一个类（对或错）

<input type="checkbox" class="tocheck-true"></input>
<input type="checkbox" class="tocheck-false"></input>

and then look for that class: 然后查找该类：

$("input.tocheck-true").prop("checked",true);

http://jsfiddle.net/mu81yz7y/ http://jsfiddle.net/mu81yz7y/

Because we're searching only for inputs that have that css class, this should perform very well. 因为我们仅在搜索具有该CSS类的输入，所以这应该表现得很好。

But, again, this seems like a complete hack. 但是，再次，这似乎是一个完整的hack。 If you're asking "how can I use duct tape to secure the engine to the body of my car," maybe you should stop to see if you should even be asking that question. 如果您问“如何使用胶带将发动机固定到汽车车身上”，也许您应该停下来看看是否应该问这个问题。 :) :)

如何检查具有布尔值的复选框

问题描述

3 个解决方案

解决方案1
4 2014-11-12 15:06:17

解决方案2
0 2014-11-12 14:47:38

解决方案3
0 2014-11-12 15:04:54

如何检查具有布尔值的复选框

问题描述

3 个解决方案

解决方案1 4 2014-11-12 15:06:17

解决方案2 0 2014-11-12 14:47:38

解决方案3 0 2014-11-12 15:04:54

解决方案1
4 2014-11-12 15:06:17

解决方案2
0 2014-11-12 14:47:38

解决方案3
0 2014-11-12 15:04:54