How to adjust height of table td based on form within iframe height

[stargazer]

My HTML:\[code\]<table> <tr> <td id="mainform"> <iframe id="ifSur"></iframe> </td> <td id="subform"></td> </tr></table>\[/code\]In iframe the \[code\]1.aspx\[/code\] page will be loaded. So the height of \[code\]subform\[/code\] \[code\]t\[/code\]d must be the height of \[code\]<form>\[/code\] tag in \[code\]1.aspx\[/code\].