验证输入字数有最大值限制并且有提示还能输入多少

               <div class="labelRight">
                    <input  onkeyup="WST.checkLength(this,'size01',15,1)" class="labelRight_tzName" type="text" name="tzName" value="{$obj['suitName']}">
                    <input type="hidden" name="suitId" id="suitId" value="{$obj['suitId']}">
                    <p>还能输入<span id="size01">15</span> 字</p>
                </div>

js部分：

WST.computeLength = function (eleInput, maxLength, nativeCharSize) {
    var nativeCharRegexp = /[u4E00-u9FFF]/;
    var string, char, length = 0;
    var ele = (typeof eleInput == 'string') ? document.getElementById(eleInput) : eleInput;
    if(maxLength == undefined) {
        maxLength = ele.maxLength || 100;
    }

    if(nativeCharSize == undefined) {
        nativeCharSize = 2;
    }

    string = (ele.value || '').split('');

    for(var i = 0, count = string.length; i < count; i ++) {
        char = string[i];
        if(nativeCharRegexp.test(char)) {
            length += nativeCharSize;
        } else {
            length ++;
        }
    }

    return length;
}

WST.checkLength = function (target,id,maxLength,zhiJie) {
    var maxLength = maxLength || 120; // 这是允许输入的最大数
    var zhiJie = zhiJie || 1; //这是区分字节的 例如汉字是2字节
    var targetLength = WST.computeLength(target, maxLength, zhiJie); // 这个是已输入的字符
    var leftLength =maxLength - targetLength;
    if(leftLength<=0){
        var val = $(target).val().slice(0,maxLength);
        $(target).val(val);
        document.getElementById(id).innerHTML = 0;
        $(target).keypress(function(event){
            var event = event || window.event;
            return false;
        });
    }else{
        document.getElementById(id).innerHTML = leftLength; // 这里的size就是需要变换数字地方的Id
    }
}