如何查看表单元素是否未发布 [英] How to see if a form element was not posted

问题描述

我有一个表格，其中电子邮件是可选的.控制是否有一个复选框.如果未选中该复选框，则电子邮件文本框将被禁用，因此不会在提交时发布.然而，在下一页，如果我有如下所示的代码，如果电子邮件文本框被禁用，它会给我一个错误.

I have a form where e-mail is optional. To control that there is a checkbox. If that checkbox is unchecked, the e-mail textbox would be disabled and therefore not posted on submit. However, on the next page, if I have code like as shown below, it gives me an error if the e-mail textbox is disabled.

if (isset($_POST['submit'])) 
{ 
    $_SESSION["email"]      = $_REQUEST['YourEMail'];
    ....
}

为了解决这个问题，除了将其值设置为空字符串之外，我还在提交之前以编程方式启用了禁用的电子邮件文本框.代码如下所示.

To get around that problem, I progammatically enable a disabled e-mail textbox just before submitting besides setting its value to an empty string. The code for that is shown below.

document.getElementById('YourEMail').disabled = false
document.getElementById('YourEMail').value = ''

然而，仍然存在一个烦人的问题，那就是，如果用户返回原始页面，电子邮件文本框会被启用，因为我在提交表单之前就启用了它有问题.但是，我希望在这种情况下禁用它.我怎样才能做到这一点?或者，如何在下一页中看到电子邮件已被禁用，因此甚至没有尝试阅读 $_REQUEST['YourEmail']?

However, one annoying problem remains, which is that, if the user goes back to the original page, the e-mail textbox is enabled, since I enabled it problematically just before submitting the form. However, I want it to be disabled in that case. How, can I achieve that? Alternatively, how in the next page, I could see that e-mail box was disabled and therefore not even try to read $_REQUEST['YourEmail']?

推荐答案

如果字段#YourEMail"是可选的，您可以检查 PHP 中是否存在.无需使用 JS 启用/禁用该字段.

if the field "#YourEMail" is optional you can check if exists in PHP. There is no need for enable/disable the field using JS.

if (isset($_POST['submit'])) 
{
    if (isset($_REQUEST['YourEMail']) && !empty($_REQUEST['YourEMail'])){
        $_SESSION["email"] = $_REQUEST['YourEMail'];
    }
}

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