计算还可以输入多少个字
Demo
html页面
<!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>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8">
<title>还可以输入多少字</title>
<meta name="keywords" content="">
<meta name="description" content="">
<script src="./jquery-1.10.2.js" type="text/javascript"></script>
<script src="./count.js" type="text/javascript"></script>
</head>
<body>
<div>
<span>
<input type="text" name="subject" id="subject" value="" onkeyup="strLenCalc(this, 'checklen', 80);" >
</span>
<span id="subjectchk">还可输入 <strong id="checklen">80</strong> 个字符</span>
</div>
</body>
</html>js代码--count.js
var BROWSER = {};
var USERAGENT = navigator.userAgent.toLowerCase();
browserVersion({'ie':'msie','firefox':'','chrome':'','opera':'','safari':'','mozilla':'','webkit':'','maxthon':'','qq':'qqbrowser','rv':'rv'});
if(BROWSER.safari || BROWSER.rv) {
BROWSER.firefox = true;
}
BROWSER.opera = BROWSER.opera ? opera.version() : 0;
HTMLNODE = document.getElementsByTagName('head')[0].parentNode;
if(BROWSER.ie) {
BROWSER.iemode = parseInt(typeof document.documentMode != 'undefined' ? document.documentMode : BROWSER.ie);
HTMLNODE.className = 'ie_all ie' + BROWSER.iemode;
}
var charset =BROWSER.firefox ? document.characterSet : document.charset;
function browserVersion(types)
{
var other = 1;
for(i in types) {
var v = types[i] ? types[i] : i;
if(USERAGENT.indexOf(v) != -1) {
var re = new RegExp(v + '(\\/|\\s|:)([\\d\\.]+)', 'ig');
var matches = re.exec(USERAGENT);
var ver = matches != null ? matches[2] : 0;
other = ver !== 0 && v != 'mozilla' ? 0 : other;
}else {
var ver = 0;
}
eval('BROWSER.' + i + '= ver');
}
BROWSER.other = other;
}
function strlen(str)
{
return (BROWSER.ie && str.indexOf('\n') != -1) ? str.replace(/\r?\n/g, '_').length : str.length;
}
function mb_cutstr(str, maxlen, dot)
{
var len = 0;
var ret = '';
var dot = !dot ? '...' : dot;
maxlen = maxlen - dot.length;
for(var i = 0; i < str.length; i++) {
len += str.charCodeAt(i) < 0 || str.charCodeAt(i) > 255 ? (charset == 'utf-8' ? 3 : 2) : 1;
if(len > maxlen) {
ret += dot;
break;
}
ret += str.substr(i, 1);
}
return ret;
}
function strLenCalc(obj, checklen, maxlen)
{
var v = obj.value;
var charlen = 0;
var maxlen = !maxlen ? 200 : maxlen;
var curlen = maxlen;
var len = strlen(v);
for(var i = 0; i < v.length; i++)
{
if(v.charCodeAt(i) < 0 || v.charCodeAt(i) > 255) {
curlen -= charset == 'utf-8' ? 2 : 1;
}
}
if(curlen >= len) {
$("#"+checklen)[0].innerHTML = curlen - len;
} else {
obj.value = mb_cutstr(v, maxlen, 0);
}
}本文参与 腾讯云自媒体分享计划，分享自作者个人站点/博客。
原始发表：2014-07-02 ，如有侵权请联系 cloudcommunity@tencent.com 删除
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