function fontChange(str){
	var cssFile;
	switch(str){
	case "small":
		cssFile="css/font_small.css";
	break;
	case "medium":
		cssFile="css/font_medium.css";
	break;
	case "big":
		cssFile="css/font_large.css";
	break;
	default:
		alert("error");
	break;
	}
	document.cookie="fontstyle="+cssFile+";path=/;";
	window.location.reload();
}
var name="fontstyle";
var cookie=document.cookie; 
if(-1==cookie.indexOf(name)){
	var file='css/font_small.css';
}else{
	var startPosition=cookie.indexOf(name)+name.length+1;
	var endPosition=cookie.indexOf(";",startPosition);
	if(-1==endPosition){ 
		var file=cookie.slice(startPosition);
	}else{
		var file=cookie.slice(startPosition,endPosition); 
	}
}
document.write('<link rel="stylesheet" href="'+file+'" type="text/css" />');