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;
        // 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 = 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() {
        if (this.currentPage > 1){
            this.showPage(this.currentPage - 1);
			$('next').style.visibility = "visible";
		}
		if (this.currentPage == 1){
			$('prev').style.visibility = "hidden";
		}
    }

    this.next = function() {
        if (this.currentPage < this.pages) {
            this.showPage(this.currentPage + 1);
			$('prev').style.visibility = "visible";
			$('next').style.visibility = "visible";
        }
		if (this.currentPage == this.pages) {
			$('next').style.visibility = "hidden";
		}
    }

    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, prev, next) {
		if(this.pages<=1) {
			$('pageNavPosition').style.visibility = "hidden";
		}
    	if (!prev) prev = '&#171; Prev';
    	if (!next) next = 'Next &#187;';
    	if (! this.inited) {
    		alert("not inited");
    		return;
    	}
    	var element = document.getElementById(positionId);
		var pagerHtml = '';
		pagerHtml += '<span id="prev" style="visibility:hidden;cursor:pointer;" onclick="' + pagerName + '.prev();" class="pg-normal"> ' + prev + '</span> ';
		for (var page = 1; page <= this.pages; page++){
			//pagerHtml += '<span id="pg' + page + '" class="pg-normal" onclick="' + pagerName + '.showPage(' + page + ');">' + page + '</span> | ';
			pagerHtml += '| <span id="pg' + page + '" class="pg-normal" >' + page + '</span> ';
		}
		pagerHtml += '<span id="next" style="cursor:pointer;" onclick="'+pagerName+'.next();" class="pg-normal"> ' + next + '</span>';
		element.innerHTML = pagerHtml;
    }
}