function Pager(tableName, itemsPerPage) {
    this.tableName = tableName;
    this.itemsPerPage = itemsPerPage;
	this.numOfPage = 3;
    this.currentPage = 0;
    this.pages = 0;
    this.inited = false;
    this.pagerName = "";
    this.positionIds = new Array();
    
    this.addPositionId = function(positionId) {
    	var idx = this.positionIds.length;
    	this.positionIds[idx] = positionId;
    }
    
    this.checkExistingPositionId = function(positionId) {
    	for(i=0;i<this.positionIds.length;i++)
    		if(this.positionIds[i]==positionId) {
    			return true;
    		}
    	return false;
    }    
    
    this.showRecords = function(from, to) {                
    	var rows = document.getElementById(tableName).rows;
        // i starts from 1 to skip table header row
        for (var i = 0; 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) {
    		return;
    	}
    	
    	for(i=0;i<this.positionIds.length;i++) {
    		var oldPageAnchor = document.getElementById('pg_' + this.positionIds[i] + this.currentPage);
	        oldPageAnchor.className = 'pg-normal';
    	}
    	this.currentPage = pageNumber;
    	for(i=0;i<this.positionIds.length;i++) {
	        this.showPageNav(this.pagerName, this.positionIds[i]);
	        var newPageAnchor = document.getElementById('pg_' + this.positionIds[i] + this.currentPage).parentNode;
	        newPageAnchor.className = 'selected';
    	}
    	        
        var from = pageNumber * itemsPerPage;
        var to = from + itemsPerPage;
        this.showRecords(from, to);
    }   
    
    this.prev = function() {
    	if (this.currentPage > 0)
        	this.showPage(this.currentPage - 1);
    }
    
    this.next = function() {		
    	if (this.currentPage < (this.pages-1)) {
        	this.showPage(this.currentPage + 1);
        }
    }                        
    
    this.init = function() {
    	var rows = document.getElementById(tableName).rows;
        var records = rows.length; 
        this.pages = Math.ceil(records / itemsPerPage); 
		if (records > itemsPerPage)
			this.inited = true;
		else
			this.inited = false;
    }

    this.showPageNav = function(pagerName, positionId) {
    	if (! this.inited) { 
    		return;
    	}
    	var element = document.getElementById(positionId);
    	
		/// DEFINE HOW MANY NUMBER DISPLAY IN ROW
    	var numOfPagination = this.numOfPage;
		
    	this.pagerName = pagerName;
    	if(this.checkExistingPositionId(positionId)==false)
    		this.addPositionId(positionId);
    	
		var pagerHtml = '<dl class="listPageNav"><dd><a href="#nogo" onclick="' + pagerName + '.prev();" class="pg-normal"><span>&laquo;</span></a>';
    		
        var begin = this.currentPage;
        if(this.pages<(this.currentPage+numOfPagination)) {
        	begin = this.pages - numOfPagination;
        	if(begin<=0)
        		begin = 0;
        }	
        var i = 0;
        
        for (var page = begin; i < numOfPagination && page < this.pages; page++) { 
			pagerHtml += '<dd><a href="#nogo" id="pg_'+ positionId + page + '" class="pg-normal-numbers" onclick="' + pagerName + '.showPage(' + page + ');"><span>'+ (page + 1) +'</span></a></dd>';
        	i = i + 1;
        }
		pagerHtml += '<dd><a href="#nogo" onclick="'+pagerName+'.next()" class="pg-normal"><span>&raquo;</span></a></dd></dl>';  
        
        element.innerHTML = pagerHtml;
    }
}