Question

If I listen to the text box (textarea) key-down event, can I get the coordinates of event when user type any characters into it?

$('#textAreaId').bind('keydown', function(event) {    
    var data = event.originalEvent.touches ? event.originalEvent.touches[0] : event;
    alert(data.pageY);    
});

Answer 1

Do you want the position of the element or the position of the caret?

To get the position of the caret you can use the following function (borrowed from another question):

function getCaret(el) { 
  if (el.selectionStart) { 
    return el.selectionStart; 
  } else if (document.selection) { 
    el.focus(); 

    var r = document.selection.createRange(); 
    if (r == null) { 
      return 0; 
    } 

    var re = el.createTextRange(), 
        rc = re.duplicate(); 
    re.moveToBookmark(r.getBookmark()); 
    rc.setEndPoint('EndToStart', re); 

    return rc.text.length; 
  }  
  return 0; 
}

To get the position of the textarea element relative to the document, you use .offset:

$("#textAreaId").bind('keydown', function(event){
    var offset = $(this).offset();
    console.log(offset);
});

I put up a test case on jsFiddle.