<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
<title>Insert title here</title>
</head>
<script type="text/javascript" src="https://ajax.googleapis.com/ajax/libs/jquery/1.4.4/jquery.min.js"></script>
<script type="text/javascript">
$(function() {
$("textarea").keyup();
});
function strLenCalc(obj, checklen, maxlen) {
var v = obj.val(), charlen = 0, maxlen = !maxlen ? 200 : maxlen, curlen = maxlen, len = v.length;
for(var i = 0; i < v.length; i++) {
if(v.charCodeAt(i) < 0 || v.charCodeAt(i) > 255) {
curlen -= 1;
}
}
if(curlen >= len) {
$("#"+checklen).html("还可输入 <strong>"+Math.floor((curlen-len)/2)+"</strong> 个字").css('color', '');
$("#subBtn").removeAttr("disabled");
} else {
$("#"+checklen).html("已经超过 <strong>"+Math.ceil((len-curlen)/2)+"</strong> 个字").css('color', '#FF0000');
$("#subBtn").attr("disabled", "disabled");
}
}
</script>
<body>
<div>
<form action="index.php" >
<textarea tabindex="11" onkeyup="strLenCalc($(this), 'checklen', 280);" value="" class="px" name="subject" id="subject"></textarea>
<span id="checklen">还可输入 <strong>140</strong> 个汉字</span>
<input type="submit" id="subBtn" value="发布" />
</form>
</div>
</body>
</html>