接下来，打开这些文件并去掉除主表单元素及其子元素之外的所有内容。
Next, open each of those files and strip out everything but the main form element and its child elements.
缺省情况下，用于格式设置的空白被丢弃，简单元素和属性没有子节点。
By default, formatting white space is discarded and simple elements and attributes do not have child nodes.
清单9描述了这种变化，子元素由一个简单元素(没有子结构)组成。
This change is described in Listing 9, where the subelements of are composed in one plain element (with no substructure).
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