html约定-自闭标签，>或/> ;，以其他方式< br>或< br />
从网上学习一些教程时，我看到很多人把标签打开，例如< link ..> ，< img .. > 。但是，当我使用Netbeans编辑它们（HTML / JSP页面）时，在这些标记上显示红色背景，直到我在其中添加斜线为止。 < br> -> < br /> 。
When take some tutorial from web, I see many people leaves tags open like <link ..>, <img ..>. But when I use Netbeans to edit them (the HTML/JSP pages), it show a red background on those tags until I add the slash into them. <br> --> <br/>.
哪种方法是编写基于HTML的代码的正确方法？
Which is the correct way to write HTML-based code?
两者都适合HTML。
Both are fine for HTML. Though not for XHTML which is an XML dialect.
某些元素不需要结束符（ /> ），尽管不是XML的XHTML。标签-特别是空元素（不包含内容的元素）。例如< hr> 和< br> 。这些可以也是自闭的（< hr /> 和< br /> ）。这种自我关闭等同于在open标签之后紧接一个close标签。
Some elements do not need a closing (/>) tag - in particular empty elements (those that do not have content). Examples are <hr> and <br>. These can also be self closing (<hr /> and <br />, respectively). This self closing is equivalent to having a close tag immediately after the open tag.
对于XML，此类非关闭标签无效-必须关闭，无论是self结束或具有结束标签。因此< hr> 不是有效的XML，但是< hr /> 和 < hr>< / hr> 是。
For XML, such a non closing tag is not valid - it must be closed, either self closing or have a closing tag. So <hr> is not valid XML, but <hr /> and <hr></hr> are.
HTML不是XML，但是为了更好的兼容性，某些工具尝试发出尽可能多的XML像HTML一样。
HTML is not XML, but for better compatibility some tools try to emit as much XML like HTML as possible.