textarea輸入字數提示

LimitedNnumber('.eventBox', '.viewBox', 50)

/*
* eventBox：輸入框id或者class
* viewBox：提示元素id或者class
* textLength：限制長度
*/
function LimitedNnumber(eventBox, viewBox, textLength) {
   $(document).on('input propertychange paste keyup', eventBox, function(event){
      this.value = this.value.replace(this.value.slice(textLength), "")
      $(viewBox).html(this.value.length +"/"+ textLength)
   })
}