HTMLFormElement

HTMLFormElement 接口可以创建或者修改<form>对象;它继承了HTMLElement接口的方法和属性。

属性

继承自父类的属性，HTMLElement.

HTMLFormElement.acceptCharset (en-US): Is a DOMString that reflects the accept-charset HTML attribute, containing a list of character encodings that the server accepts.
HTMLFormElement.action: Is a DOMString that reflects the action HTML attribute, containing the URI of a program that processes the information submitted by the form.
HTMLFormElement.autocomplete: Is a DOMString that reflects the autocomplete HTML attribute, containing a string that indicates whether the controls in this form can have their values automatically populated by the browser.
HTMLFormElement.elements 只读: Returns a live HTMLFormControlsCollection (en-US) containing all the form controls belonging to this form element.
HTMLFormElement.encoding (en-US): Is a synonym for enctype.
HTMLFormElement.enctype: Is a DOMString reflects the enctype HTML attribute, indicating the type of content that is used to transmit the form to the server. Only specified values can be set.
HTMLFormElement.length (en-US) 只读: Returns a long that represents the number of controls in the form.
HTMLFormElement.method (en-US): Is a DOMString that reflects the method HTML attribute, indicating the HTTP method used to submit the form. Only specified values can be set.
HTMLFormElement.name (en-US): Is a DOMString that reflects the name HTML attribute, containing the name of the form.
HTMLFormElement.noValidate: Is a Boolean that reflects the novalidate HTML attribute, indicating that the form should not be validated.
HTMLFormElement.target (en-US): Is a DOMString that reflects the target HTML attribute, indicating where to display the results received from submitting the form.

方法

这个元素继承了 HTMLElement 的属性。

HTMLFormElement.checkValidity(): Returns a Boolean that is true if the element's child controls are subject to constraint validation and satify those contraints, or false if some controls do not satisfy their constraints. Fires an event named invalid at any control that does not satisfy its constraints; such controls are considered invalid if the event is not canceled. It is up to the programmer to decide how to respond to false.
HTMLFormElement.item(): Gets the item in the elements collection at the specified index, or null if there is no item at that index. You can also specify the index in array-style brackets or parentheses after the form object name, without calling this method explicitly.
HTMLFormElement.namedItem(): 从元素集合中获取 name 或者 id 与指定名称匹配的项，没有匹配项则返回 null。你也可以像调用数组那样用圆括号或方括号来指定名称，而不必显式地调用这个方法。
HTMLFormElement.submit(): Submits the form to the server.
HTMLFormElement.reset(): Resets the forms to its initial state.
HTMLFormElement.reportValidity(): Returns true if the element's child controls satisfy their validation constraints. When false is returned, cancelable invalid (en-US) events are fired for each invalid child and validation problems are reported to the user.

Examples

The following example shows how to create a new form element, modify its attributes and submit it.

// Create a form
var f = document.createElement("form");

// Add it to the document body
document.body.appendChild(f);

// Add action and method attributes
f.action = "/cgi-bin/some.cgi";
f.method = "POST";

// Call the form's submit method
f.submit();

In addition, the following complete HTML document shows how to extract information from a form element and to set some of its attributes.

html

<title>Form example</title>
<script type="text/javascript">
  function getFormInfo() {
    var info;

    // Get a reference using the forms collection
    var f = document.forms["formA"];
    info =
      "f.elements: " +
      f.elements +
      "\n" +
      "f.length: " +
      f.length +
      "\n" +
      "f.name: " +
      f.name +
      "\n" +
      "f.acceptCharset: " +
      f.acceptCharset +
      "\n" +
      "f.action: " +
      f.action +
      "\n" +
      "f.enctype: " +
      f.enctype +
      "\n" +
      "f.encoding: " +
      f.encoding +
      "\n" +
      "f.method: " +
      f.method +
      "\n" +
      "f.target: " +
      f.target;
    document.forms["formA"].elements["tex"].value = info;
  }

  // A reference to the form is passed from the
  // button's onclick attribute using 'this.form'
  function setFormInfo(f) {
    f.method = "GET";
    f.action = "/cgi-bin/evil_executable.cgi";
    f.name = "totally_new";
  }
</script>

<h1>Form example</h1>

<form name="formA" id="formA" action="/cgi-bin/test" method="POST">
  <p>
    Click "Info" to see information about the form. Click set to change
    settings, then info again to see their effect
  </p>
  <p>
    <input type="button" value="info" onclick="getFormInfo();" />
    <input type="button" value="set" onclick="setFormInfo(this.form);" />
    <input type="reset" value="reset" />
    <br />
    <textarea id="tex" style="height:15em; width:20em"> </textarea>
  </p>
</form>

The following example shows how to submit a form in a popup window.

html

<!doctype html>
<html>
  <head>
    <meta http-equiv="Content-Type" content="text/html; charset=UTF-8" />
    <title>MDN Example</title>
    <script type="text/javascript">
      function popupSend(oFormElement) {
        if (
          oFormElement.method &&
          oFormElement.method.toLowerCase() !== "get"
        ) {
          alert("This script supports the GET method only.");
          return;
        }
        var oField,
          sFieldType,
          nFile,
          sSearch = "";
        for (var nItem = 0; nItem < oFormElement.elements.length; nItem++) {
          oField = oFormElement.elements[nItem];
          if (!oField.hasAttribute("name")) {
            continue;
          }
          sFieldType =
            oField.nodeName.toUpperCase() === "INPUT"
              ? oField.getAttribute("type").toUpperCase()
              : "TEXT";
          if (sFieldType === "FILE") {
            for (
              nFile = 0;
              nFile < oField.files.length;
              sSearch +=
                "&" +
                escape(oField.name) +
                "=" +
                escape(oField.files[nFile++].name)
            );
          } else if (
            (sFieldType !== "RADIO" && sFieldType !== "CHECKBOX") ||
            oField.checked
          ) {
            sSearch += "&" + escape(oField.name) + "=" + escape(oField.value);
          }
        }
        open(
          oFormElement.action.replace(/(?:\?.*)?$/, sSearch.replace(/^&/, "?")),
          "submit-" + (oFormElement.name || Math.floor(Math.random() * 1e6)),
          "resizable=yes,scrollbars=yes,status=yes",
        );
      }
    </script>
  </head>

  <body>
    <form
      name="yourForm"
      action="test.php"
      method="get"
      onsubmit="popupSend(this); return false;">
      <p>
        First name: <input type="text" name="firstname" /><br />
        Last name: <input type="text" name="lastname" /><br />
        Password: <input type="password" name="pwd" /><br />
        <input type="radio" name="sex" value="male" /> Male
        <input type="radio" name="sex" value="female" /> Female
      </p>
      <p>
        <input type="checkbox" name="vehicle" value="Bike" />I have a bike<br />
        <input type="checkbox" name="vehicle" value="Car" />I have a car
      </p>
      <p><input type="submit" value="Submit" /></p>
    </form>
  </body>
</html>

Submitting forms and uploading files using `XMLHttpRequest`

If you want to know how to serialize and submit a form using the XMLHttpRequest API, please read this paragraph.

Specifications

Specification
HTML Standard # htmlformelement

Browser compatibility

BCD tables only load in the browser

属性

方法

Examples

Submitting forms and uploading files using XMLHttpRequest

Specifications

Browser compatibility

See also

Submitting forms and uploading files using `XMLHttpRequest`