textarea输入框限制输入字符的方法
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<title>textarea限制输入字符</title>
</head>
<body>
<textarea...
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<title>textarea限制输入字符</title>
</head>
<body>
<textarea name='test' onkeyup='textAreaChange(this)' onkeydown='textAreaChange(this)' rows='5'></textarea>
<div class='text-right'>
<em style='color:red'>200</em>/<span>200</span>
</div>
</body>
<script src="http://libs.baidu.com/jquery/1.11.3/jquery.min.js"></script>
<script type="text/javascript">
//显示限制输入字符method
function textAreaChange(obj){
var $this = $(obj);
var count_total = $this.next().children('span').text();
var count_input = $this.next().children('em');
var area_val = $this.val();
if(area_val.len()>count_total){
area_val = autoAddEllipsis(area_val,count_total);//根据字节截图内容
$this.val(area_val);
count_input.text(0);//显示可输入数
}else{
count_input.text(count_total - area_val.len());//显示可输入数
}
}
//得到字符串的字节长度
String.prototype.len = function(){
return this.replace(/[^\x00-\xff]/g, "xx").length;
};
/*
* 处理过长的字符串，截取并添加省略号
* 注：半角长度为1，全角长度为2
* pStr:字符串
* pLen:截取长度
* return: 截取后的字符串
*/
function autoAddEllipsis(pStr, pLen) {
var _ret = cutString(pStr, pLen);
var _cutFlag = _ret.cutflag;
var _cutStringn = _ret.cutstring;
return _cutStringn;
}
/*
* 取得指定长度的字符串
* 注：半角长度为1，全角长度为2
* pStr:字符串
* pLen:截取长度
* return: 截取后的字符串
*/
function cutString(pStr, pLen) {
// 原字符串长度
var _strLen = pStr.length;
var _tmpCode;
var _cutString;
// 默认情况下，返回的字符串是原字符串的一部分
var _cutFlag = "1";
var _lenCount = 0;
var _ret = false;
if (_strLen <= pLen/2){_cutString = pStr;_ret = true;}
if (!_ret){
for (var i = 0; i < _strLen ; i++ ){
if (isFull(pStr.charAt(i))){_lenCount += 2;}
else {_lenCount += 1;}
if (_lenCount > pLen){_cutString = pStr.substring(0, i);_ret = true;break;}
else if(_lenCount == pLen){_cutString = pStr.substring(0, i + 1);_ret = true;break;}
}
}
if (!_ret){_cutString = pStr;_ret = true;}
if (_cutString.length == _strLen){_cutFlag = "0";}
return {"cutstring":_cutString, "cutflag":_cutFlag};
}
/*
* 判断是否为全角
*
* pChar:长度为1的字符串
* return: true:全角
* false:半角
*/
function isFull (pChar){
if((pChar.charCodeAt(0) > 128)){return true;}
else{return false;}
}
</script>
</html>
- 发表于 2020-06-25 21:52
- 阅读 ( 449 )
- 分类：web前端开发
