Foldlink = function(cnt,cn,sn,hn) {
    this.view_count = cnt ? cnt : 3;
    this.ul_name = cn ? cn : 'pr';
    this.show_name = sn ? sn : 'prs';
    this.hide_name = hn ? hn : 'prh';
}

Foldlink.prototype.elem = new Array();
Foldlink.prototype.elem_show_btn;
Foldlink.prototype.elem_hide_btn;

Foldlink.prototype.init = function() {
    var elem_ul = document.getElementsByTagName('ul');
    
    for (var i=0;i<elem_ul.length;i++) {
        if(elem_ul[i].className===this.ul_name){
            var elem_li = elem_ul[i].getElementsByTagName('li');
            for(var j=0;j<elem_li.length;j++){
                this.elem[j] = elem_li[j];
            }
        }
    }
    
    var elem_span = document.getElementsByTagName('span');
    for (var i=0;i<elem_span.length;i++) {
        if(elem_span[i].className===this.show_name) {
            this.elem_show_btn = elem_span[i];
        } else if(elem_span[i].className===this.hide_name) {
            this.elem_hide_btn = elem_span[i];
        }
    }
    
    this.hide();
    
}

Foldlink.prototype.hide = function() {
    for (var i=0;i<this.view_count;i++) {
        this.elem[i].style.display='list-item';
    }
    for (var i=this.view_count;i<this.elem.length;i++) {
        this.elem[i].style.display='none';
    }
    this.elem_hide_btn.style.display='none';
    this.elem_show_btn.style.display='inline';
}

Foldlink.prototype.show = function() {
    for (var i=0;i<this.elem.length;i++) {
        this.elem[i].style.display='list-item';
    }
    this.elem_show_btn.style.display='none';
    this.elem_hide_btn.style.display='inline';
}