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

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 containing all the form controls belonging to this form element.

HTMLFormElement.encoding

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 只读

Returns a long that represents the number of controls in the form.

HTMLFormElement.method

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

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

Is a DOMString that reflects the target HTML attribute, indicating where to display the results received from submitting the form.

Methods

Inherits methods from its parent, HTMLElement.

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()

Gets the item or list of items in elements collection whose name or id match the specified name, or null if no items match. You can also specify the name in array-style brackets or parentheses after the form object name, without calling this method explicitly.

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 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.

<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.

<!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

Browser compatibility

See also

• The HTML element implementing this interface: <form>.