add an iframe code example
Example 1: html iframe example
<iframe src="http://www.codegrepper.com"></iframe>
Example 2: put html in iframe
<iframe srcdoc="<html><body>Hello, <b>world</b>.</body></html>"></iframe>
<iframe src="http://www.codegrepper.com"></iframe>
<iframe srcdoc="<html><body>Hello, <b>world</b>.</body></html>"></iframe>