HTML/CSS/Frame Attributes/allowtransparency
"allowtransparency" creates the transparent frames
<source lang="html4strict">
<HTML> <Title>Example For allowtransparency</Title> <BODY> <iframe src="http://www.wbex.ru" allowTransparency="true"
style="width:40%;background-color:transparent">
</iframe> <iframe src="http://www.wbex.ru" style="width: 40%; background-color: green"> </iframe> <iframe src="http://www.wbex.ru"
allowTransparency="false" style="width:40%;background-color:white">
</iframe> <iframe src="http://www.wbex.ru"
allowTransparency ="true" style="width:40%; background-color:lightgreen">
</iframe> </BODY> </HTML>
</source>