<!DOCTYPE html> <html lang="en"> <head> <meta charset="UTF-8"> <title>Title</title> <style> body { margin: 0px; padding: 0px; } .if-top { display: block; border: none; width: 100%; height: 120px; } .if-menu { width: 20%; border: none; } .if-content { width: 78%; border: none; } </style> </head> <body> <iframe class="if-top" src="top.html"></iframe> <iframe class="if-menu" src="menu.html"></iframe> <iframe class="if-content" src="content.html"></iframe> </body> </html>
在上面的top iframe里面加上
display: block;