function Pager(tableName, itemsPerPage, positionId) {
    this.tableName = tableName;
    this.positionId = positionId;
    this.itemsPerPage = itemsPerPage;
    this.currentPage = 1;
    this.pages = 0;
    this.inited = false;

    this.showRecords = function(from, to) {
        var rows = document.getElementById(tableName).rows;
        // i starts from 1 to skip table header row
        for (var i = 1; i < rows.length; i++) {
            if (i < from || i > to)
                rows[i].style.display = 'none';
            else
                rows[i].style.display = '';
        }
    }

    this.showPage = function(pageNumber) {
    	if (! this.inited) {
    		alert("not inited");
    		return;
    	}

        var oldPageAnchor = $('.pg'+this.currentPage);
        oldPageAnchor.removeClass('pg-selected');
        oldPageAnchor.addClass('pg-normal');

        this.currentPage = pageNumber;
        var newPageAnchor = $('.pg'+this.currentPage);
        newPageAnchor.removeClass('pg-normal');
        newPageAnchor.addClass('pg-selected');

        var from = (pageNumber - 1) * itemsPerPage + 1;
        var to = from + itemsPerPage - 1;
        this.showRecords(from, to);

        var pgNext = $(".pgNext");
        var pgPrev = $(".pgPrev");
        if (this.currentPage == this.pages)
            pgNext.css("display", 'none');
        else
            pgNext.css("display", '');

        if (this.currentPage == 1)
            pgPrev.css("display",'none');
        else
            pgPrev.css("display",'');

    }

    this.prev = function() {
        if (this.currentPage > 1)
            this.showPage(this.currentPage - 1);
    }

    this.next = function() {
        if (this.currentPage < this.pages) {
            this.showPage(this.currentPage + 1);
        }
    }

    this.init = function() {
        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("not inited");
    		return;
    	}
    	var element = document.getElementById(positionId);

	    var pagerHtml = '<span class="pgPrev" onclick="' + pagerName + '.prev();" class="pg-normal"> &#171 Prev </span> | ';

	    for (var page = 1; page <= this.pages; page++)
	    			pagerHtml += '<span class="pg' + page + '" class="pg-normal" onclick="' + pagerName + '.showPage(' + page + ');">' + page + '</span> | ';

        pagerHtml += '<span class="pgNext" onclick="'+pagerName+'.next();" class="pg-normal"> Next &#187;</span>';

        element.innerHTML = pagerHtml;
    }
}