//获取字符串的字节长度 function getStringByteLength(str){
    var realLength = 0;   for (var i = 0; i < str.length; i++)   {
      charCode = str.charCodeAt(i);     if (charCode >= 0 && charCode <= 128)       realLength += 1;     else       realLength += 2;   }   return realLength; } //按字节截取字符串长度 function cutOutStringByteLength(str,long) {
    var seeString = [];   var countByteLength = 0;   for(var i=0;i
    
     = 0 && charCode <= 128){
        countByteLength += 1;     }else{
        countByteLength += 2;     }     if (countByteLength <= long){
        seeString.push(str[i]);     }   }   return seeString.join(""); }