$(document).ready(function() {
	//when key is pressed in the textbox
	$("#length,#height,#width").keypress(function (e)
	{
	  //if the letter is not digit then don't type anything
	  if( e.which != 46 && e.which!=8 && e.which!=0 && (e.which<48 || e.which>57))
	  {
		return false;
	  }
	});
});