Only allow numeric values in a text input.

Restrict text field to only be numeric

// Only allow numbers in a text field

$(".class").keydown(function(event) {
  // Allow: backspace, delete, tab, escape, and enter
  if ( event.keyCode == 46 || event.keyCode == 8 || event.keyCode == 9 || event.keyCode == 27 || event.keyCode == 13 ||
      // Allow: Ctrl+A
    (event.keyCode == 65 && event.ctrlKey === true) ||
      // Allow: home, end, left, right
    (event.keyCode >= 35 && event.keyCode <= 39)) {
      // let it happen, don't do anything
    return;
  } else {
    // Ensure that it is a number and stop the keypress
    if (event.shiftKey || (event.keyCode < 48 || event.keyCode > 57) && (event.keyCode < 96 || event.keyCode > 105 )) {
        event.preventDefault();
    }
  }
});