/*
*长度跟踪器
*v2.1.0
*bind2Id:用于显示长度变化的元素的id
*max:最大长度
*msgWrap:提示信息(必须要有一个"-"占位符)
*eg:$('#input').lenTracer({bind2Id:'myTracer',max:150,msgWrap:'您还可以输入-个字符'});
*author:liujg1015@gmail.com
*/
(function ($) {
var zw_validate = function (el, option) {
this.el = $(el);
this.bindEl = false;
this.setting = {
bind2Id: false,
max: 100,
msgWrap: '您还可以输入-个字符'
};
if (option) {
$.extend(this.setting, option);
this.init();
}
};
zw_validate.prototype = {
init: function () {
var _this = this;
this.bindEl = $('#' + this.setting.bind2Id);
this.el.focus(function () { _this.start(); }).blur(function () { _this.dispose(); });
this.el.css({ paddingBottom: 20 });
this.initMsg();
},
initMsg: function () {
var wrap = this.setting.msgWrap.split('-');
this.bindEl.text(this.setting.max - this.count().total).before(wrap[0]).after(wrap[1]);
},
count: function () {
var _val = this.el.val();
var _len = _val.length;
var _rowCount = 0;
var _enterLen = 0;
var _partten = /\n+/g;
if (_len > 0 && _partten.test(_val)) {
_enterLen += 3;
while ((result = _partten.exec(_val)) != null) {
if ((result.index + 1 + _enterLen) > this.setting.max) {
break;
}
_enterLen += 3;
}
_rowCount = _val.match(_partten).length;
}
return { total: (_len + _rowCount * 3), enterLen: _enterLen };
},
start: function () {
var _this = this;
_this.timer = setInterval(function () {
var _val = _this.el.val();
var _rlt = _this.count();
if (_rlt.total > _this.setting.max) {
if (_rlt.enterLen > 0) {
_this.el.val(_val.substr(0, _this.setting.max - _rlt.enterLen));
}
else {
_this.el.val(_val.substr(0, _this.setting.max));
}
_this.bindEl.text(_this.setting.max - _this.count().total);
return;
}
_this.bindEl.text(_this.setting.max - _rlt.total);
}, 300);
},
dispose: function () {
clearInterval(this.timer);
},
restore: function () {
this.bindEl.text(this.setting.max - this.el.val().length);
}
};
$.fn.extend({
lenTracer: function (option) {
return new zw_validate(this, option);
}
});
})(jQuery);
一、上面是计数器的脚本，可将脚本贴到js文件中，然后在html里面添加引用。
<html>
<head>
<title>demo</title>
</head>
<body>
<table>
<tr>
<td>
标题
</td>
<td>
<input type="text" id="title" />
<span id="titlelen"></span>
</td>
</tr>
<tr>
<td>
评论
</td>
<td>
<textarea cols="5" rows="5" id="comment"></textarea>
<span id="commentlen"></span>
</td>
</tr>
</table>
<script src="../scripts/jquery.js" type="text/javascript"></script>
<script src="../scripts/lentracer.js" type="text/javascript"></script>
<script type="text/javascript">
$(document).ready(function(){
$('#title).lenTracer({ bind2Id: titlelen, max: 50});
$('#comment).lenTracer({ bind2Id: commentlen, max: 200, msgWrap: '剩余-字' });
});
</script>
</body>
</html>
二、上面的代码是展示如何使用。
这个计数器是自己用jQuery写的，因此要依赖于jQuery库函数。能计算回车符，因为在textarea里面的回车符提交到后台后是'\r\n'。欢迎批评、指正。
