$("#form input, #form select, #form textarea").each(function() {
 data[theFieldName] = theFieldValue;
});

除此之外，你可能想看看serialize();

我有点惊讶，因为下面没有人提到解决方案。

通过document.forms.namedItem函数获取表单数据

var form = document.forms.namedItem("fileinfo");

form.addEventListener('submit', function(ev) {
   var oData = new FormData(form);
}

HT的

<form name="fileinfo">
  <label>Your email address:</label>
  <input type="email" autocomplete="on" autofocus name="userid" placeholder="email" required size="32" maxlength="64" /><br />
  <label>Custom file label:</label>
  <input type="text" name="filelabel" size="12" maxlength="32" /><br />
  <label>File to stash:</label>
  <input type="file" name="file" required />
  <input type="submit" value="Stash the file!" />
</form>
<div></div>

这个方法应该可以做到。它序列化表单数据，然后将它们转换为对象。还可以处理复选框组。

function getFormObj(formId) {
  var formParams = {};
  $('#' + formId)
    .serializeArray()
    .forEach(function(item) {
      if (formParams[item.name]) {
        formParams[item.name] = [formParams[item.name]];
        formParams[item.name].push(item.value)
      } else {
        formParams[item.name] = item.value
      }
    });
  return formParams;
}

$('form').serialize() //this produces: "foo=1&bar=xxx&this=hi"

demo

document.querySelector('form').addEventListener('submit', (e) => {
  const formData = new FormData(e.target);
  // Now you can use formData.get('foo'), for example.
  // Don't forget e.preventDefault() if you want to stop normal form .submission
});

这是一个吹毛求疵的答案，但让我解释为什么这是一个更好的解决方案:

We're properly handling a form submit rather than a button press. Some people like to push enter on fields. Some people use alternative input devices such as speech input or other accessibility devices. Handle the form submit and you correctly solve it for everyone. We're digging into the form data for the actual form that was submitted. If you change your form selector later, you don't have to change the selectors for all the fields. Furthermore, you might have several forms with the same input names. No need to disambiguate with excessive IDs and what not, just track the inputs based on the form that was submitted. This also enables you to use a single event handler for multiple forms if that is appropriate for your situation. The FormData interface is fairly new, but is well supported by browsers. It's a great way to build that data collection to get the real values of what's in the form. Without it, you're going to have to loop through all the elements (such as with form.elements) and figure out what's checked, what isn't, what the values are, etc. Totally possible if you need old browser support, but the FormData interface is simpler. I'm using ES6 here... not a requirement by any means, so change it back to be ES5 compatible if you need old browser support.

$("#form input, #form select, #form textarea").each(function() {
 data[theFieldName] = theFieldValue;
});

除此之外，你可能想看看serialize();