Perhaps the most frequent claim to the Opera browser is incorrect page display. Meanwhile, a paradox arises: this browser most fully supports modern web standards, but at the same time it is most often reproached for poor-quality page processing. What's the matter? In his blog, Haavard decided to dissect one of these “tricky” pages and found out that its authors initially configured JavaScript to work only in two browsers - Internet Explorer and Netscape / Firefox. In his article, he gives a detailed analysis of the problem code, which leaves no chance to the Norwegian browser.