[varjag]

var a = e.keyCode;
  return !!(a==0
          ||a==8/*backspace*/
          ||a==46/*delete*/
          ||(a>=112 && a<=123) /*F1-F12*/
          ||(a>=96 && a<=105) /*NumPad 0 - NumPad 9*/
          ||(a>=33 && a<=40) /*PageUp, PageDown, End, Home, arrows (left,right,up,down)*/
          ||(e.ctrlKey && (a == 88/*ctrl+x*/ || a == 67/*ctrl+c*/ || a == 86/*ctrl+v*/ || a == 90/*ctrl+z*/))
          ||(!e.shiftKey && (a>=48 && a<=57)));//[0-9]