function is_numeric( field ) {

	if( field.value.length == 0 && String.fromCharCode(event.keyCode) == '-' )	return true;
	
	return /\d/.test(String.fromCharCode(event.keyCode));
}

function is_float( field )	// unsigned float
{
	if( field.value.length == 0 && String.fromCharCode(event.keyCode) == '-' )	return true;
		
	if(  /\d/.test(String.fromCharCode(event.keyCode))																	||
		 (  event.type == 'keypress' && event.keyCode == 46 && field.value.indexOf('.') < 0 )		||
		 ( (event.type == 'keyup' || event.type == 'keydown') && event.keyCode == 190  && field.value.indexOf('.') < 0 )  )		return true;
		 
	return false;
}