function ch(){
    var data = document.getElementById("data");
	var span = data.getElementsByTagName("span");

	var now = 0;
    if(!span[0]) return false;
    
	var left = document.getElementById('lbn');
	var right = document.getElementById('rbn');

	left.onclick = function(){
        now--;
		if(now < 0){
            now = span.length - 1;
		}

		var js = 'var dy1 = new dyobject("' + span[now].innerHTML + '", "204", "152");dy1.write("div1")';
		eval(js);
		return false;
	}

	right.onclick = function(){
        now++;
		if(now >= span.length){
            now = 0;
		}
        
		var js = 'var dy1 = new dyobject("' + span[now].innerHTML + '", "204", "152");dy1.write("div1")';
		eval(js);
		return false; 
	}
    
	var js = 'var dy1 = new dyobject("' + span[now].innerHTML + '", "204", "152");dy1.write("div1")';
	eval(js);	
}