If link tag can be inserted in body tag, and inserts importee's document.body to importer, then it would be easily without any scripts.
An example is below: component.html: <!DOCTYPE html> <div> <p class="name">Hong Gildong</p> <p class="age">20</p> </div> index.html: <!DOCTYPE html> <html lang="en-US"> <head> <title>Human Being</title> </head> <body> <link rel="import" href="component.html"> </body> </html>