How to force input to only allow Alpha Letters?

Question

using jQuery here, however unable to prevent numbers from being typed into the input field

http://codepen.io/leongaban/pen/owbjg

Input

Answer 1

A lot of the other solutions that use keypress will not work on mobile, you need to use input.

html

jQuery

$('#name').on('input', function() {
    var cursor_pos = $(this).getCursorPosition()
    if(!(/^[a-zA-Z ']*$/.test($(this).val())) ) {
        $(this).val($(this).attr('data-value'))
        $(this).setCursorPosition(cursor_pos - 1)
        return
    }
    $(this).attr('data-value', $(this).val())
})

$.fn.getCursorPosition = function() {
    if(this.length == 0) return -1
    return $(this).getSelectionStart()
}
$.fn.setCursorPosition = function(position) {
    if(this.lengh == 0) return this
    return $(this).setSelection(position, position)
}
$.fn.getSelectionStart = function(){
  if(this.lengh == 0) return -1
  input = this[0]
  var pos = input.value.length
  if (input.createTextRange) {
    var r = document.selection.createRange().duplicate()
    r.moveEnd('character', input.value.length)
    if (r.text == '') 
    pos = input.value.length
    pos = input.value.lastIndexOf(r.text)
  } else if(typeof(input.selectionStart)!="undefined")
  pos = input.selectionStart
  return pos
}
$.fn.setSelection = function(selectionStart, selectionEnd) {
  if(this.lengh == 0) return this
  input = this[0]
  if(input.createTextRange) {
    var range = input.createTextRange()
    range.collapse(true)
    range.moveEnd('character', selectionEnd)
    range.moveStart('character', selectionStart)
    range.select()
  }
  else if (input.setSelectionRange) {
    input.focus()
    input.setSelectionRange(selectionStart, selectionEnd)
  }
  return this
}