<g:else></g:else>else
<g:elseif></g:elseif>else if
<g:encodeAs codec=""></g:encodeAs>指定编码格式的encode
<g:escapeJavascript></g:escapeJavascript>
<g:escapeJavascript>This is some "text" to be escaped</g:escapeJavascript>
<g:external/>
Render the appropriate kind of external link for use in <head> based on the type of the URI. For JS will render <script> tags, for CSS will render <link> with the correct rel, and so on for icons.