Template Doctypes
if you want to use any HTML entities (such as & < > or ©), you must use an HTML or XHTML doctype in your template. If you choose to use (X)HTML doctypes in your templates, they will be passed on to the client in the resultant (X)HTML. Note that if your pages are composed of multiple components, each with a template, and each template contains a doctype declaration, only the first doctype encountered by the template parser will be passed on to the client.
br /> "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
假如需要输入Html字符，比如& 等等，就需要在模板文件声明 DOCTYPE.