Multiple browsers are vulnerable to the Dialog Origin Spoofing Vulnerability
Secunia Research has discovered a vulnerability in various browsers, which can be exploited by malicious web sites to spoof dialog boxes. The problem is that JavaScript dialog boxes do not display or include their origin, which allows a new window to open e.g. a prompt dialog box, which appears to be from a trusted site.
If you go to the test page, please make sure no critical applications are open and test cautiously:
Secunia Browser - Dialog Origin Vulnerability Test