简单的JavaScript复选框验证 [英] Simple JavaScript Checkbox Validation

问题描述

我通常用PHP工作，所以很遗憾没有一些基本的JS原则。这就是我想要完成的 - 我在这个主题上看到了很多帖子，但它们通常超出了我的需要。

I usually work with PHP so sadly don't have some basic JS principles down. This is all I want to accomplish--I've seen many posts on this topic but they are usually beyond what I need.

这是我的表单：

 <input type="checkbox" name="checkbox" value="check"  />
 <input type="submit" name="email_submit" value="submit" onclick="----??----"  />

复选框是一个简单的我同意。我希望提交按钮被按下，只有在选中该复选框时才会提交。

The checkbox is a simple "I agree". I want the submit button to be pressed and it will only submit if that check box is selected.

以下是事情：我想要一个简单的，作弊的方法 - 没有方法 - 这种形式只是一些内联代码（假设它不会太长？）。这不是一个公共页面，我只需要用这种验证方式快速而简单的事情。如果未选中，它会抛出alert（）;如果它被选中，它将通过php提交并且照常进行。

Here's the thing: I want the simple, cheating way -- no methods -- just some inline code in that form (assuming its not overly long?). This is not a public page, I just need something quick and simple with that type of validation. If its unchecked, it will throw an alert(); if its checked it will submit via post through php and go on as normal.

推荐答案

您可以使用：

 if(!this.form.checkbox.checked)
{
    alert('You must agree to the terms first.');
    return false;
}

（

(demo page).

<input type="checkbox" name="checkbox" value="check"  />
<input type="submit" name="email_submit" value="submit" onclick="if(!this.form.checkbox.checked){alert('You must agree to the terms first.');return false}"  />

• 返回 false 从内联事件处理程序将阻止默认操作发生（在本例中，提交表单）。 布尔运算符。


• 是提交按钮，因为它是事件处理程序附加到的元素。


• .form 是提交按钮的形式。


• .checkbox 是表单中名为checkbox的控件。
>

• .checked 如果复选框处于选中状态，则为true;如果复选框处于未选中状态，则为false。
  
  • Returning false from an inline event handler will prevent the default action from taking place (in this case, submitting the form).
  • ! is the Boolean NOT operator.
  • this is the submit button because it is the element the event handler is attached to.
  • .form is the form the submit button is in.
  • .checkbox is the control named "checkbox" in that form.
  • .checked is true if the checkbox is checked and false if the checkbox is unchecked.

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