function Pager(tableName, itemsPerPage) {
    this.tableName = tableName;
    this.itemsPerPage = itemsPerPage;
    this.currentPage = 1;
    this.pages = 0;
    this.inited = false;
    
    this.showRecords = function(from, to) {        
        var rows = document.getElementById(tableName).rows;
		$('.emptyrow').remove();
		// alert('filas>>' + rows);
        // i starts from 1 to skip table header row
        for (var i = 1; i < rows.length; i++) {		      
			  // alert(rows[i].innerHTML);
            if (i < from || i > to)  
                rows[i].style.display = 'none';
            else
                rows[i].style.display = '';				
        }
		
    }
    
    this.showPage = function(pageNumber) {
	$('.emptyrow').remove();
	if(pageNumber == 1){
			$("#prev").attr("style","display:none;");
	}else{
		var maxPageNumber = $("#maxfield").html();
		if(pageNumber == maxPageNumber-1){
			$("#next").attr("style","display:none;");
		}else{
			$("#prev").removeAttr("style");
		}	
	}
	
	$("#number"+pageNumber).html(pageNumber);

    	if (! this.inited) {
    		alert("Error 1 !");
    		return;
    	}

        var oldPageAnchor = document.getElementById('pg'+this.currentPage);
        oldPageAnchor.className = 'pg-normal';
        
        this.currentPage = pageNumber;
        var newPageAnchor = document.getElementById('pg'+this.currentPage);
        newPageAnchor.className = 'pg-selected';
        
        var from = (pageNumber - 1) * itemsPerPage + 1;
        var to = from + itemsPerPage - 1;
        this.showRecords(from, to);
    }   
    
    this.prev = function(numAct) {
        if (numAct > 1)
            this.showPage(numAct - 1);
			return numAct - 1;
    }
    
    this.next = function(numAct) {
        if (numAct < this.pages) {
            this.showPage(numAct + 1);
			return numAct + 1;
        }
    }                        
    
    this.init = function() {
	    $('.emptyrow').remove();
        var rows = document.getElementById(tableName).rows;
        var records = (rows.length - 1); 
        this.pages = Math.ceil(records / itemsPerPage);
        this.inited = true;
    }

    this.showPageNav = function(pagerName, positionId) {
    	if (! this.inited) {
    		alert("Error 2 !");
    		return;
    	}
    	var element = document.getElementById(positionId);
    	
    	var pagerHtml = 'P&aacute;gina: <span id="prev" onclick="prev();" class="pg-normal" style="size:12px;" onmouseover="this.style.cursor=\'pointer\'"> (<a href="#">Anterior</a>) </span> | ';
        for (var page = 1; page <= this.pages; page++) 
            pagerHtml += '<span id="pg' + page + '" class="pg-normal" onclick="mostrarPagina(' + page + ')"  style="size:12px;" onmouseover="this.style.cursor=\'pointer\'"><span id="number'+page+'"><a href="#">' + page + '</a></span></span> | ';
        pagerHtml += '<span id="next" onclick="next();" class="pg-normal" style="size:12px;" onmouseover="this.style.cursor=\'pointer\'"> (<a href="#">Siguiente</a>)</span><div id="maxfield" style="display:none;">'+page+'</div>';            
        
        element.innerHTML = pagerHtml;
    }
}