HTMLTextAreaElement

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特性
方法
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范例
规范
浏览器兼容性
相关话题

HTMLTextAreaElement interface provides special properties and methods for manipulating the layout and presentation of <textarea> 元素。

  <div id="interfaceDiagram" style="display: inline-block; position: relative; width: 100%; padding-bottom: 20%; vertical-align: middle; overflow: hidden;"><svg style="display: inline-block; position: absolute; top: 0; left: 0;" viewbox="-50 0 600 120" preserveAspectRatio="xMinYMin meet"><a xlink:href="../API/EventTarget.html" target="_top"><rect x="1" y="1" width="110" height="50" fill="#fff" stroke="#D4DDE4" stroke-width="2px" /><text  x="56" y="30" font-size="12px" font-family="Consolas,Monaco,Andale Mono,monospace" fill="#4D4E53" text-anchor="middle" alignment-baseline="middle">EventTarget</text></a><polyline points="111,25  121,20  121,30  111,25" stroke="#D4DDE4" fill="none"/><line x1="121" y1="25" x2="151" y2="25" stroke="#D4DDE4"/><a xlink:href="../API/Node" target="_top"><rect x="151" y="1" width="75" height="50" fill="#fff" stroke="#D4DDE4" stroke-width="2px" /><text  x="188.5" y="30" font-size="12px" font-family="Consolas,Monaco,Andale Mono,monospace" fill="#4D4E53" text-anchor="middle" alignment-baseline="middle">Node</text></a><polyline points="226,25  236,20  236,30  226,25" stroke="#D4DDE4" fill="none"/><line x1="236" y1="25" x2="266" y2="25" stroke="#D4DDE4"/><a xlink:href="../API/Element" target="_top"><rect x="266" y="1" width="75" height="50" fill="#fff" stroke="#D4DDE4" stroke-width="2px" /><text  x="303.5" y="30" font-size="12px" font-family="Consolas,Monaco,Andale Mono,monospace" fill="#4D4E53" text-anchor="middle" alignment-baseline="middle">Element</text></a><polyline points="341,25  351,20  351,30  341,25" stroke="#D4DDE4" fill="none"/><line x1="351" y1="25" x2="381" y2="25" stroke="#D4DDE4"/><a xlink:href="../API/HTMLElement" target="_top"><rect x="381" y="1" width="110" height="50" fill="#fff" stroke="#D4DDE4" stroke-width="2px" /><text  x="436" y="30" font-size="12px" font-family="Consolas,Monaco,Andale Mono,monospace" fill="#4D4E53" text-anchor="middle" alignment-baseline="middle">HTMLElement</text></a><polyline points="491,25  501,20  501,30  491,25" stroke="#D4DDE4" fill="none"/><line x1="501" y1="25" x2="509" y2="25" stroke="#D4DDE4"/><line x1="509" y1="25" x2="509" y2="90" stroke="#D4DDE4"/><line x1="509" y1="90" x2="492" y2="90" stroke="#D4DDE4"/><a xlink:href="../API/HTMLTextAreaElement" target="_top"><rect x="301" y="65" width="190" height="50" fill="#F4F7F8" stroke="#D4DDE4" stroke-width="2px" /><text  x="396" y="94" font-size="12px" font-family="Consolas,Monaco,Andale Mono,monospace" fill="#4D4E53" text-anchor="middle" alignment-baseline="middle">HTMLTextAreaElement</text></a></svg></div>

  a:hover text { fill: #0095DD; pointer-events: all;}

特性

`accessKey`	`string :` Returns / Sets the element's `accesskey` 属性。
`autocapitalize`	`string :` Returns / Sets the element's capitalization behavior for user input. Valid values are: `none` , `off` , `characters` , `words` , `sentences` .
`autocomplete`
`autofocus`	`boolean :` Returns / Sets the element's `autofocus` attribute, indicating that the control should have input focus when the page loads
`cols`	`unsigned long :` Returns / Sets the element's `cols` attribute, indicating the visible width of the text area.
`defaultValue`	`string :` Returns / Sets the control's default value, which behaves like the `Node.textContent` 特性。
`被禁用`	`boolean :` Returns / Sets the element's `被禁用` attribute, indicating that the control is not available for interaction.
`form` 只读	`object :` Returns a reference to the parent form element. If this element is not contained in a form element, it can be the `id` attribute of any `<form>` element in the same document or the value `null` .
`inputMode`
`maxLength`	`long :` Returns / Sets the element's `maxlength` attribute, indicating the maximum number of characters the user can enter. This constraint is evaluated only when the value changes.
`minLength`	`long :` Returns / Sets the element's `minlength` attribute, indicating the minimum number of characters the user can enter. This constraint is evaluated only when the value changes.
`名称`	`string :` Returns / Sets the element's `名称` attribute, containing the name of the control.
`placeholder`	`string :` Returns / Sets the element's `placeholder` attribute, containing a hint to the user about what to enter in the control.
`readOnly`	`boolean :` Returns / Sets the element's `readonly` attribute, indicating that the user cannot modify the value of the control.
`required`	`boolean :` Returns / Sets the element's `required` attribute, indicating that the user must specify a value before submitting the form.
`rows`	`unsigned long :` Returns / Sets the element's `rows` attribute, indicating the number of visible text lines for the control.
`selectionDirection`	`string :` Returns / Sets the direction in which selection occurred. This is " `forward` " if selection was performed in the start-to-end direction of the current locale, or " `backward` " for the opposite direction. This can also be " `none` " if the direction is unknown.
`selectionEnd`	`unsigned long :` Returns / Sets the index of the end of selected text. If no text is selected, contains the index of the character that follows the input cursor. On being set, the control behaves as if `setSelectionRange()` had been called with this as the second argument, and `selectionStart` as the first argument.
`selectionStart`	`unsigned long :` Returns / Sets the index of the beginning of selected text. If no text is selected, contains the index of the character that follows the input cursor. On being set, the control behaves as if `setSelectionRange()` had been called with this as the first argument, and `selectionEnd` as the second argument.
`tabIndex`	`long :` Returns / Sets the position of the element in the tabbing navigation order for the current document.
`textLength` 只读	`long :` Returns the codepoint length of the control's `value` . Same as reading `value.length`
`type` 只读	`string :` 返回字符串 `textarea` .
`validationMessage` 只读	`string :` Returns a localized message that describes the validation constraints that the control does not satisfy (if any). This is the empty string if the control is not a candidate for constraint validation ( `willValidate` is `false` ), or it satisfies its constraints.
`validity` 只读	`ValidityState 对象 :` Returns the validity states that this element is in.
`value`	`string :` Returns / Sets the raw value contained in the control.
`willValidate` 只读	`boolean :` Returns whether the element is a candidate for constraint validation. `false` if any conditions bar it from constraint validation, including its `readOnly` or `被禁用` 特性为 `true` .
`wrap`	`string :` Returns / Sets the `wrap` HTML attribute, indicating how the control wraps text.
`HTMLTextAreaElement.labels` 只读	`NodeList` : Returns a list of label elements associated with this element.

The two properties tabIndex and accessKey are inherited from HTMLElement from HTML5 on, but were defined on HTMLTextAreaElement in DOM Level 2 HTML and earlier specifications.

方法

`blur()`	Removes focus from the control; keystrokes will subsequently go nowhere.
`focus()`	Gives focus to the control; keystrokes will subsequently go to this element.
`select()`	Selects the contents of the control.
`setRangeText()`	Replaces a range of text in the element with new text.
`setSelectionRange()`	Selects a range of text in the element (but does not focus it).
`checkValidity()`	返回 `false` if the element is a candidate for constraint validation, and it does not satisfy its constraints. In this case, it also fires a cancelable `无效` event at the control. It returns `true` if the control is not a candidate for constraint validation, or if it satisfies its constraints.
`reportValidity()`	This method reports the problems with the constraints on the element, if any, to the user. If there are problems, it fires a cancelable `无效` event at the element, and returns `false` ; if there are no problems, it returns `true` .
`setCustomValidity(DOMstring)`	Sets a custom validity message for the element. If this message is not the empty string, then the element is suffering from a custom validity error, and does not validate.

The two methods blur() and focus() are inherited from HTMLElement from HTML5 on, but were defined on HTMLTextAreaElement in DOM Level 2 HTML and earlier specifications.

事件

监听这些事件使用 addEventListener() 或通过把事件监听器赋值给 on eventname property of this interface:

input event: Fires when the value of an <input> , <select> ，或 <textarea> 元素已改变。

范例

Autogrowing textarea example

Make a textarea autogrow while typing:

JavaScript

function autoGrow (oField) {
  if (oField.scrollHeight > oField.clientHeight) {
    oField.style.height = oField.scrollHeight + "px";
  }
}

CSS

textarea.noscrollbars {
  overflow: hidden;
  width: 300px;
  height: 100px;
}

HTML

<form>
  <fieldset>
    <legend>Your comments</legend>
    <p><textarea class="noscrollbars" onkeyup="autoGrow(this);"></textarea></p>
    <p><input type="submit" value="Send" /></p>
  </fieldset>
</form>

Insert HTML tags example

Insert some HTML tags or smiles or any custom text in a textarea.

JavaScript

function insertMetachars(sStartTag, sEndTag) {
  var bDouble = arguments.length > 1, oMsgInput = document.myForm.myTxtArea, nSelStart = oMsgInput.selectionStart, nSelEnd = oMsgInput.selectionEnd, sOldText = oMsgInput.value;
  oMsgInput.value = sOldText.substring(0, nSelStart) + (bDouble ? sStartTag + sOldText.substring(nSelStart, nSelEnd) + sEndTag : sStartTag) + sOldText.substring(nSelEnd);
  oMsgInput.setSelectionRange(bDouble || nSelStart === nSelEnd ? nSelStart + sStartTag.length : nSelStart, (bDouble ? nSelEnd : nSelStart) + sStartTag.length);
  oMsgInput.focus();
}

CSS

CSS to decorate the internal span to behave like a link:

.intLink {
  cursor: pointer;
  text-decoration: underline;
  color: #0000ff;
}

HTML:

<form name="myForm">
<p>[ <span class="intLink" onclick="insertMetachars('<strong>','<\/strong>');"><strong>Bold</strong></span> | <span class="intLink" onclick="insertMetachars('<em>','<\/em>');"><em>Italic</em></span> | <span class="intLink" onclick="var newURL=prompt('Enter the full URL for the link');if(newURL){insertMetachars('<a href=\u0022'+newURL+'\u0022>','<\/a>');}else{document.myForm.myTxtArea.focus();}">URL</span> | <span class="intLink" onclick="insertMetachars('\n<code>\n','\n<\/code>\n');">code</span> | <span class="intLink" onclick="insertMetachars(' :-)');">smile</span> | etc. etc. ]</p>
<p><textarea name="myTxtArea" rows="10" cols="50">Lorem ipsum dolor sit amet, consectetur adipiscing elit. Ut facilisis, arcu vitae adipiscing placerat, nisl lectus accumsan nisi, vitae iaculis sem neque vel lectus. Praesent tristique commodo lorem quis fringilla. Sed ac tellus eros. Sed consectetur eleifend felis vitae luctus. Praesent sagittis, est eget bibendum tincidunt, ligula diam tincidunt augue, a fermentum odio velit eget mi. Phasellus mattis, elit id fringilla semper, orci magna cursus ligula, non venenatis lacus augue sit amet dui. Pellentesque lacinia odio id nisi pulvinar commodo tempus at odio. Ut consectetur eros porttitor nunc mollis ultrices. Aenean porttitor, purus sollicitudin viverra auctor, neque erat blandit sapien, sit amet tincidunt massa mi ac nibh. Proin nibh sem, bibendum ut placerat nec, cursus et lacus. Phasellus vel augue turpis. Nunc eu mauris eu leo blandit mollis interdum eget lorem. </textarea></p>
</form>

Maximum length and number of lines example

Create a textarea with a maximum number of characters per line and a maximum number of lines:

First, create a function that takes the text field and a key event as input and determines if any of the limits have been reached. If the limit has not been reached, it will return the key.

function checkRows(oField, oKeyEvent) {
  var nKey = (oKeyEvent || /* old IE */ window.event || /* check is not supported! */ { keyCode: 38 }).keyCode,
    // put here the maximum number of characters per line:
    nCols = 30,
    // put here the maximum number of lines:
    nRows = 5,
    nSelS = oField.selectionStart, nSelE = oField.selectionEnd,
    sVal = oField.value, nLen = sVal.length,
    nBackward = nSelS >= nCols ? nSelS - nCols : 0,
    nDeltaForw = sVal.substring(nBackward, nSelS).search(new RegExp("\\n(?!.{0," + String(nCols - 2) + "}\\n)")) + 1,
    nRowStart = nBackward + nDeltaForw,
    aReturns = (sVal.substring(0, nSelS) + sVal.substring(nSelE, sVal.length)).match(/\n/g),
    nRowEnd = nSelE + nRowStart + nCols - nSelS,
    sRow = sVal.substring(nRowStart, nSelS) + sVal.substring(nSelE, nRowEnd > nLen ? nLen : nRowEnd),
    bKeepCols = nKey === 13 || nLen + 1 < nCols || /\n/.test(sRow) || ((nRowStart === 0 || nDeltaForw > 0 || nKey > 0) && (sRow.length < nCols || (nKey > 0 && (nLen === nRowEnd || sVal.charAt(nRowEnd) === "\n"))));
  return (nKey !== 13 || (aReturns ? aReturns.length + 1 : 1) < nRows) && ((nKey > 32 && nKey < 41) || bKeepCols);
}

In the HTML we just need to hook our function to the `onkeypress` event and specify that our textarea does not accept pasting:

<form>
  <p>Textarea with fixed number of characters per line:<br />
    <textarea cols="50" rows="10" onkeypress="return checkRows(this, event);"
              onpaste="return false;"></textarea>
  </p>
</form>

规范

规范	状态	注释
HTML 实时标准 The definition of 'HTMLTextAreaElement' in that specification.	实时标准
HTML5 The definition of 'HTMLTextAreaElement' in that specification.	推荐	属性 `tabindex` and `accesskey` , as well as the methods `blur()` and `focus()` are now defined on `HTMLElement` . The following attributes have been added: `autofocus` , `placeholder` , `dirName` , `wrap` , `maxLength` , `required` , `textLength` , `labels` , `selectionStart` , `selectionEnd` , `selectionDirection` , `validity` , `validationMessage` ，和 `willValidate` . The following methods have been added: `checkValidity()` , `setCustomValidity()` ，和 `setSelectionRange()` .
DOM (文档对象模型) 2 级 HTML 规范 The definition of 'HTMLTextAreaElement' in that specification.	过时	The property `defaultValue` doesn't contain the initial value of the `value` attribute, but the initial value of the content of the `<textarea>` .
DOM (文档对象模型) 1 级规范 The definition of 'HTMLTextAreaElement' in that specification.	过时	初始定义

浏览器兼容性

The compatibility table on this page is generated from structured data. If you'd like to contribute to the data, please check out https://github.com/mdn/browser-compat-data and send us a pull request. 更新 GitHub 上的兼容性数据

	桌面						移动
	Chrome	Edge	Firefox	Internet Explorer	Opera	Safari	Android webview	Chrome for Android	Firefox for Android	Opera for Android	Safari on iOS	Samsung Internet
`HTMLTextAreaElement`	Chrome 1	Edge 12	Firefox 1	IE 8	Opera 8	Safari 3	WebView Android 1	Chrome Android 18	Firefox Android 4	Opera Android 10.1	Safari iOS 1	Samsung Internet Android 1.0
`autocapitalize`	Chrome 43	Edge 79	Firefox ?	IE ?	Opera ?	Safari ?	WebView Android No	Chrome Android 43	Firefox Android ?	Opera Android ?	Safari iOS ?	Samsung Internet Android 4.0
`autocomplete`	Chrome 66	Edge ≤79	Firefox Yes	IE ?	Opera Yes	Safari Yes	WebView Android 66	Chrome Android 66	Firefox Android Yes	Opera Android Yes	Safari iOS Yes	Samsung Internet Android 9.0
`labels`	Chrome 14	Edge 18	Firefox 56	IE No	Opera Yes	Safari Yes	WebView Android Yes	Chrome Android Yes	Firefox Android 56	Opera Android Yes	Safari iOS Yes	Samsung Internet Android Yes
`reportValidity`	Chrome 40	Edge 17	Firefox 49	IE No	Opera 27	Safari 10	WebView Android 40	Chrome Android 40	Firefox Android 64	Opera Android 27	Safari iOS 10	Samsung Internet Android 4.0
`textLength`	Chrome 47	Edge 17	Firefox 28	IE No	Opera 30	Safari 9	WebView Android Yes	Chrome Android Yes	Firefox Android Yes	Opera Android Yes	Safari iOS Yes	Samsung Internet Android Yes

图例

完整支持
不支持
兼容性未知 ?

元数据

最后修改： Jul 22, 2020

在此页

特性

方法

事件

范例

Autogrowing textarea example

JavaScript

CSS

HTML

Insert HTML tags example

JavaScript

CSS

Maximum length and number of lines example

规范

浏览器兼容性

图例

相关话题