javascript create iframe-自动创建头部和身体标签

Question

It appears that

document.createElement('iframe');

automatically creates head and body tags.

I've tested this in Firefox,Chrome and IE9+.

Is this the standard or other browsers might not react like this. I'm asking this because I wanna know if I need to check if those tags are created before inserting some elements in them. If I can avoid the check condition I'll be more than happy because I want to keep my js code as light as I can.

Answer 1

As far as I now, it's not standard, but supported by all common browsers. The standard only defines that there is a HTML tag, so

document.documentElement

is supported. You can check for:

document.documentElement.children.length > 0