textarea输入字符有限制

function limitedNumberOfInputCharacters(limitedNumber, string){
    var strLength = 0;
   if(string !== null || string !== ""){
        strLength = string.length;
   }
   if(strLength>limitedNumber){
        strLength = limitedNumber;
   }
   var leftLength = limitedNumber - strLength; //剩余个数
   console.log("您还可以输入"+leftLength + "个字符");

}