What is iframe src attribute?
The HTML <iframe> src attribute is used to specify the URL of the document that are embedded to the <iframe> element. Syntax: <iframe src="URL"> Attribute Values: It contains single value URL which specifies the URL of the document that is embedded to the iframe.
Which iframe attributes are not supported in HTML5?
The <Iframe> Tag Attributes
Note − The frameborder, marginwidth, longdesc, scrolling, marginheight attributes deprecated in HTML5. Do not use these attributes. This attribute is used to give the file name that should be loaded in the frame. Its value can be any URL.