insert html into php variable

I am using phpmailer for a rich html mailer and I have been using lines like this to build up the mailbody $mail_body .= "<div align=\"center\"><img src=\"http://www.myurl.org/mylogo.gif\"; Is there a build in function to assign html code to a php variable and then output them? Or can I read an external php file into a variable? <div id="container"> div id="content-top">thsi is some content</div> <div id="content-middle"> <div id="logos"></div> <div id="content-bottom"> </div> many thanks, R.