JavaScript for循环无法在功能键按下时使用

Question

In my code for alert all the lines of textarea filed on every keydown event but loop not working

function limitTextareaLine(e) {

  var textArray = $(this).val().split("\n");
  for(var v in textArray){ // Only iterate first line
    alert(textArray[v] +" "+textArray.length); 
  }

}

$(function() {
    $('textarea.limited').keydown(limitTextareaLine);
});

Answer 1

In Javascript you need to loop through the array using numbers, you were using the values in the array. You need the following:

function limitTextareaLine(e) {

  var textArray = $(this).val().split("\n");
  for(v=0; v < textArray.length; v++){
    alert(textArray[v] +" "+textArray.length); 
  }

}

$(function() {
    $('textarea.limited').keyup(limitTextareaLine);
});

I've also changed the event to keyup so that it triggers the event after the key has been recorded in the box.