(Quick Reference)
                pageProperty
Purpose
Used in layouts to output the contents a property of the decorated page. Equivalent to the SiteMesh 
<decorator:getProperty/> tag.
Examples
Example decorated page:
<html>
   <head>
        <meta name="layout" content="myLayout" />
        <script src="myscript.js" />
   </head>
   <body onload="alert('hello');">Page to be decorated</body>
</html>
Example decorator layout:
<html>
   <head>
        <script src="global.js" />
        <g:layoutHead />
   </head>
   <body onload="${pageProperty(name:'body.onload')}"><g:layoutBody /></body>
</html>
Results in:
<html>
   <head>
        <script src="global.js" />
        <script src="myscript.js" />
   </head>
   <body onload="alert('hello');">Page to be decorated</body>
</html>Source