What does the browser do when the source of iframe is javascript

Question

When the source of an iframe is:

javascript:'';

as in:

<iframe id="SpControlFrame1" name="SpControlFrame1" src="javascript:'';" path_src="index.php?cmd=YYY" ></iframe>

What is going on? What does the src="javascript:'';" tell the browser to do?

what does the "path_src" do?

Thanks Chris

Answer 1

It tells the browser to display the result of executing the empty string literal. Therefore, it would just display an empty string.

You can test the effect of this by typing in javascript:'http://stackoverflow.com'; in the address bar of a normal window/tab. You'll get a white page that says "http://stackoverflow.com" and you won't actually be taken to that URL.

This is the reason that bookmarklets often wrap the code inside void() or an anonymous function that doesn't return anything to stop the browser from trying to display the result of executing the bookmarklet. For example:

javascript:void(window.open("dom_spy.html"))

Or:

javascript:(function () { window.open("dom_spy.html"); })()

If you directly use code that returns something (a new window instance in this case), the browser will end up displaying that:

javascript:window.open("dom_spy.html");

In Firefox the above will display:

[object Window]