未捕获的TypeError：无法将属性'className'设置为null [英] Uncaught TypeError: Cannot set property 'className' of null

问题描述

我正在使用js文件对表进行分页。当我尝试单击下一页按钮时发生错误。它只是显示错误，如未捕获的TypeError：无法设置属性'className'为null。

I am using js file for paginate a table. It occurs an error while I am trying to click on next page button. It just show the error like this "Uncaught TypeError: Cannot set property 'className' of null".

这是我的代码：

    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'; 

推荐答案

它失败，因为没有带有id的DOM元素 'PG' + this.currentPage 。如果这是正常行为，那么您可以将 className 调用包装在中，如果块：

It fails because there is no DOM element with the id 'pg'+this.currentPage. If this is normal behavior, then you can just wrap the className call in an if block:

var oldPageAnchor = document.getElementById('pg'+this.currentPage);
if (oldPageAnchor) {
   oldPageAnchor.className = 'pg-normal';
}

否则，您需要发布更多代码以向我们展示 this.currentPage 在JavaScript中设置，以及它正在运行的HTML。

Otherwise, you'll need to post more code to show us where this.currentPage is set in JavaScript, and the HTML on which it is acting.

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