如何讓不需要的滾動條消失？

我正在嘗試爲多個尺寸的屏幕設置響應網站，例如自舉尺寸爲xs,sm,md和lg。如何讓不需要的滾動條消失？

一切正常工作在三個較小的尺寸，即滾動條只在需要時出現在右側。

然而，大尺寸屏幕，具有1,024像素寬度，這樣它不會過寬，我怎樣才能在需要時垂直滾動條只出現？

較小的尺寸確定：

大尺寸具有不需要時不必要的滾動條：

.pagecontent { 
 
    margin: 0 18px; 
 
} 
 
/* bootstrap override */ 
 

 
.container { 
 
    width: 100%; 
 
    padding: 0; 
 
} 
 
.navbar { 
 
    border-radius: 0px; 
 
} 
 
.navbar-text { 
 
    float: left !important; 
 
    margin-right: 10px; 
 
} 
 
.navbar-right { 
 
    float: right!important; 
 
} 
 
.navbar-nav>li>a { 
 
    padding-top: 15px; 
 
    padding-bottom: 15px; 
 
} 
 
.navbar-nav { 
 
    margin-bottom: 0; 
 
    margin-top: 0; 
 
    margin-left: 0; 
 
} 
 
.container { 
 
    width: 1024px; 
 
    padding: 0; 
 
    background-color: #fff; 
 
    position: absolute; 
 
    top: 0; 
 
    bottom: 0; 
 
    left: 0; 
 
    right: 0; 
 
    overflow-y: scroll; 
 
} 
 
html { 
 
    min-height: 100%; 
 
    /* make sure it is at least as tall as the viewport */ 
 
    position: relative; 
 
} 
 
body { 
 
    height: 100%; 
 
    /* force the BODY element to match the height of the HTML element */ 
 
    background-color: #999; 
 
}

<!DOCTYPE html> 
 
<html> 
 

 
<head> 
 
    <script src="//ajax.googleapis.com/ajax/libs/jquery/1.11.3/jquery.min.js"></script> 
 
    <meta name="viewport" content="width=device-width, initial-scale=1"> 
 
    <link rel="stylesheet" href="https://maxcdn.bootstrapcdn.com/bootstrap/3.3.6/css/bootstrap.min.css"> 
 
    <script src="https://netdna.bootstrapcdn.com/bootstrap/3.3.6/js/bootstrap.min.js"></script> 
 

 
</head> 
 

 
<body> 
 

 
    <div class="container"> 
 
    <nav class="navbar navbar-inverse"> 
 
     <div class="container-fluid"> 
 
     <div class="navbar-header pull-left"> 
 
      <a class="navbar-brand" href="?">Bootstrap Showcase</a> 
 
     </div> 
 

 
     </div> 
 
    </nav> 
 
    <div class="pagecontent"> 
 

 
     <div>this is a test line</div> 
 
     <div>this is a test line</div> 
 
     <div>this is a test line</div> 
 
     <div>this is a test line</div> 
 
     <div>this is a test line</div> 
 
     <div>this is a test line</div> 
 
     <div>this is a test line</div> 
 
     <div>this is a test line</div> 
 
     <div>this is a test line</div> 
 
     <div>this is a test line</div> 
 
     <div>this is a test line</div> 
 
     <div>this is a test line</div> 
 
     <div>this is a test line</div> 
 
     <div>this is a test line</div> 
 
     <div>this is a test line</div> 
 
     <div>this is a test line</div> 
 
     <div>this is a test line</div> 
 
     <div>this is a test line</div> 
 

 
    </div> 
 
    </div> 
 
</body> 
 

 
</html>

附錄：

如果我刪除overflow-y: scroll，我得到右邊的滾動條，但隨後的內容前下方伸出：