I thought macs didn’t get viruses. I guess that’s a myth.
And this IS NOT A VIRUS. it's not even truly Malware—it's not installed on the computer, downloaded to it, or even running on it—it's a maliciously designed website that uses a particularly long recurring requestor loop in a JAVA script to give the illusion that your browser has been locked. In a way, you might call it a Quasi-Trojan, but it fails to meet even the loose definition of a Trojan horse app. It's more of a snare, a trap, or perhaps a puzzle page.
Like all computers on which applications can be downloaded and installed, Macs ARE vulnerable to Trojan Horse Applications that claim to offer a benefit but also carry a malevolent payload. These use "Social Engineering" means to persuade the user to install the malware themselves. There are currently about forty known Trojans for Mac OSX in about seven families. Apple Mac OSX has a built-in system to identify these known trojans and any variants based on them. OSX warns the user if he attempts to download, install, or run one of these known or variant Trojans. Apple pushes updates as necessary. These Trojans are not considered "viruses" by definition.
A computer virus is malware that is self-replicating, self-transmitting, and self-installing. There have been about fifteen or sixteen attempts at creating a true OSX virus in the past twelve years. . . all have been abject failures for a simple reason: the lack of a viable vector in OSX that could be exploited to promulgate the infection, and the lack of a reliable method of guaranteed installation. One candidate used Blutooth as a vector to transmit his virus. However, it took two Macworld techs, and two Semantic security engineers SIX HOURS just to get it to copy itself from one Mac to another. . . And then, it wouldn't run because it hadn't installedh! Another was successful in copying itself to another Mac via WIFI as data, but was stymied because the data stacks on Macs are hardware non-executable memory locations and code cannot be executed in data stacks. FAIL!
So, Macs are pretty secure when it comes to malware, compared to the competition. . . And it's not because of obscurity. It's by design.