I'm demo1.html. I'm an external (iframed) document. It looks like I'm a part of the containing document, because I have been made 'seamless'. For clarity reasons, my text is colored green.
My width: 100%.
The code that created me (in the main page):
<iframe style="width: 100%" src="about:blank" name="seamless_ifr" onload="for (var i = 0; i < document.getElementsByTagName('style').length; i++) {frames['seamless_ifr'].document.getElementsByTagName('head')[0].appendChild(document.getElementsByTagName('style')[i].cloneNode(true))}; this.style.height=0; this.style.borderWidth=0; this.scrolling='no'; this.style.verticalAlign='top'; frames['seamless_ifr'].document.body.style.padding=0; frames['seamless_ifr'].document.body.style.margin=0; this.style.height=Math.max(frames['seamless_ifr'].document.body.scrollHeight, frames['seamless_ifr'].document.body.offsetHeight, frames['seamless_ifr'].document.documentElement.clientHeight, frames['seamless_ifr'].document.documentElement.scrollHeight, frames['seamless_ifr'].document.documentElement.offsetHeight) -1 +'px'; if(frames['seamless_ifr'].location.href=='about:blank'){frames['seamless_ifr'].location.href='demo1.html'}; ">
</iframe>