Javascript 文本区域最大长度检查
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Textarea maxlength check
提问by Hulk
Textarea validation,
文本区域验证，
How to limit the characters in a textareafor not exceeding more than 50 characters.
如何限制 a 中的字符textarea不超过 50 个字符。
<textarea rows="5" cols="15"></textarea>
Thanks.....
谢谢.....
回答by zaf
Using:
使用：
<textarea rows="5" cols="15" maxlength="50"></textarea>
From http://sigswitch.com/2008/07/textarea-maxlength-with-jquery/:
从http://sigswitch.com/2008/07/textarea-maxlength-with-jquery/：
$(document).ready(function(){
$('textarea[maxlength]').keyup(function(){
var max = parseInt($(this).attr('maxlength'));
if($(this).val().length > max){
$(this).val($(this).val().substr(0, $(this).attr('maxlength')));
}
$(this).parent().find('.charsRemaining').html('You have ' + (max - $(this).val().length) + ' characters remaining');
});
});
回答by Marcus L
One Google away.
一个谷歌了。
<script language="javascript" type="text/javascript">
<!--
function imposeMaxLength(Object, MaxLen)
{
return (Object.value.length <= MaxLen);
}
-->
</script>
Implementation:
<textarea name="myName" onkeypress="return imposeMaxLength(this, 50);" ></textarea>
EDIT:
编辑：
Code that doesn't freeze text:
不冻结文本的代码：
<script type="text/javascript">
/***********************************************
* Textarea Maxlength script- ? Dynamic Drive (www.dynamicdrive.com)
* This notice must stay intact for legal use.
* Visit http://www.dynamicdrive.com/ for full source code
***********************************************/
function imposeMaxLength(obj){
var mlength=obj.getAttribute? parseInt(obj.getAttribute("maxlength")) : ""
if (obj.getAttribute && obj.value.length>mlength){
obj.value=obj.value.substring(0,mlength)
}
</script>
<textarea maxlength="40" onkeyup="return imposeMaxLength(this)"></textarea>
回答by Dss
Much simpler inline method:
更简单的内联方法：
<textarea cols="60" rows="5" onkeypress="if (this.value.length > 100) { return false; }"></textarea>
Change the "100" to however many characters you want
将“100”更改为您想要的任意字符数
回答by Surinder
<asp:TextBox ID="txtColumn2" runat="server" TextMode="MultiLine" MaxLength="500" onkeyDown="checkTextAreaMaxLength(this,event,'500');"
onblur="onBlurTextCounter(this,'500');"></asp:TextBox>
function checkTextAreaMaxLength(textBox, e, maxLength) {
if (!checkSpecialKeys(e)) {
if (textBox.value.length > maxLength - 1) {
if (window.event)//IE
e.returnValue = false;
else//Firefox
e.preventDefault();
}
}
onBlurTextCounter(textBox, maxLength);
}
function checkSpecialKeys(e) {
if (e.keyCode != 8 && e.keyCode != 46 && e.keyCode != 37 && e.keyCode != 38 && e.keyCode != 39 && e.keyCode != 40)
return false;
else
return true;
}
function onBlurTextCounter(textBox, maxLength) {
if (textBox.value.length > maxLength)
textBox.value = textBox.value.substr(0, maxLength);
}
回答by Dror
I don't know of a built in HTML way but you can use this:
我不知道内置的 HTML 方式，但您可以使用它：
<textarea rows="5" cols="15" onkeydown="return validateCharLimit(this);"></textarea>??????????????
function validateCharLimit(area)
{
var limit = 50;
var iChars = area.value.length;
if (iChars > limit) {
return false;
}
return true;
}
回答by nik
<script>
function chkLen()
{
var tlen=document.getElementById('myTA').value.length;
if(tlen>50)
{
document.getElementById('myTA').value.substr(0,49)
}
}
</script>
<body>
<textarea id="myTA" onkeyup='chkLen()'></textarea>
</body>
回答by Fawad Ghafoor
Limit Number of Characters in a TextArea using jQuery
使用 jQuery 限制 TextArea 中的字符数
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
<head>
<title>Limit Number of Characters in a TextArea</title>
<script type='text/javascript' src='http://jqueryjs.googlecode.com/files/jquery-1.3.2.min.js'></script>
<script type='text/javascript'>
$(document).ready(function() {
$('#ta').keyup(function() {
var len = this.value.length;
if (len >= 50) {
this.value = this.value.substring(0, 50);
}
$('#charLeft').text(50 - len);
});
});
</script>
</head>
<body>
<textarea id="ta" cols="15" rows="5"></textarea><br/>
(Maximum characters: 50)<br/>
<span id="charLeft"> </span> Characters left
</body>
回答by detale
Here's a solution utilizaing HTML 5 textarea's "maxLength" attribute and jQuery 1.7+.
这是一个利用HTML 5 textarea 的“maxLength”属性和 jQuery 1.7+的解决方案。
1. Add "maxLength" attribute to textarea
1.为textarea添加“maxLength”属性
<textarea cols="35" rows="3" maxLength="255" id="myTextArea" name="myTextArea">
</textarea>
2. Add jQuery event handler for the textarea
2.为textarea添加jQuery事件处理程序
$(function() {
$('#myTextArea').on('input propertychange', function () {
var propMaxLength = $(this).prop('maxLength');
if (!propMaxLength || typeof propMaxLength != 'number') {
var maxLength = $(this).attr('maxlength'), txt = $(this).val();
if (txt.length > maxLength) {
$(this).val(txt.substr(0, maxLength));
}
}
});
});
