享元模式

运用共享技术有效的支持大量的细粒度的对象，避免对象间拥有相同内容造成多余的开销

// 享元对象
var Flyweight = function () {    
  var created = [];    
  function create() {        
  var dom = document.createElement('div');          
  document.getElementById('container').appendChild(dom);        
  created.push(dom);        
  return dom;    
}    
return {        
  getDiv : function() {            
    if (created.length < 5) {                
        return create();            
      } else {                
        var div = created.shift();                
        created.push(div);                
        return div;            
      }        
    }    
  }
}();
// 实现需求
var paper = 0,    
      num = 5,    
      len = article.length;
for (var i=0; i<5; i++) {    
    if (article[i]) {        
       Flyweight.getDiv().innerHTML = article[i];    
    }
}
document.getElementById('next_page').onclick = function () {    
  if (article.length < 5) {        
    return    
  }    
  var n = ++paper  * num % len,        
        j = 0;    
  for (; j < 5; j++) {        
    if (article[n + j]) {            
      Flyweight.getDiv().innerHTML = article[n + j];        
    } else if (article[n + j - len]) {            
      Flyweight.getDiv().innerHTML = article[n + j - len];        
    } else {            
      Flyweight.getDiv().innerHTML = "";        
    }    
  }
}