多行文本溢出

;(function($){
    //多行文本溢出
    $.fn.dot=function(num){
        var _num=!num?140:num;
        var realLength = 0,
            text=$(this).text(),
            length = text.length;
        for (var i = 0; i < length; i++) {
            var charCode = text.charCodeAt(i);
            if (charCode >= 0 && charCode <= 128) {
                realLength += 1;
            } else {
                realLength += 2;
            }
            if(realLength>_num){
                break;
            }
        }
        if(i<length){      
            var newStr=text.substr(0,i)+"...";
            $(this).text(newStr);
        }
        return this;
    }
})(jQuery)