function security_check() {

	if ( document.getElementById('captcha').value == "" || document.getElementById('captcha').value == "security" ){
	
		alert("Please type in the characters you see \nin the image to the left of this box");

		document.getElementById('captcha').focus();
		
	}else{
	
		if ( document.getElementById('captcha').value == code.substr(sub,6) ){
		
			submit_calculator() ;
			
		}else{

			alert ("Please type in the characters you see \nin the image to the left of this box");

		}
		
	
	}
}