{"id":3113,"date":"2015-11-05T14:37:36","date_gmt":"2015-11-05T03:37:36","guid":{"rendered":"http:\/\/blog.mozilla.org\/nnethercote\/?p=3113"},"modified":"2015-11-05T14:37:36","modified_gmt":"2015-11-05T03:37:36","slug":"moz-icon-a-curious-corner-of-firefox","status":"publish","type":"post","link":"https:\/\/blog.mozilla.org\/nnethercote\/2015\/11\/05\/moz-icon-a-curious-corner-of-firefox\/","title":{"rendered":"moz-icon: a curious corner of Firefox"},"content":{"rendered":"

Here’s an odd little feature in Firefox. Enter the following text into the address bar.<\/p>\n

 moz-icon:\/\/.pdf?size=128<\/pre>\n
On my Linux box, it shows the following icon image.<\/p>\n
\"pdf-icon-linux\"<\/a><\/p>\n
On my Windows laptop, it shows a different icon image.<\/p>\n
\"pdf-icon-windows\"<\/a><\/p>\n
On my Mac Laptop, that URL doesn’t work but if I change the “128” to “64” it shows this icon image.<\/p>\n
\"pdf-icon-mac\"<\/a><\/p>\n
In each case we get the operating system’s icon for a PDF file.<\/p>\n
Change the “size” (up to a maximum of 255) value and you’ll get a different size. Except on Mac the limit seems to be lower, probably due to the retina screen in some way.<\/p>\n
Change the file extension and you’ll get a different icon. You can try all sorts, like “.xml”, “.cpp”, “.js”, “.py”, “.doc”, etc.<\/p>\n
How interesting. So what’s this for? As far as I understand, it’s used to make local directory listing pages look nice. E.g. on my Linux box if I type “file:\/\/\/home\/njn\/” into the address bar I get a listing of my home directory, part of which looks like the following.<\/p>\n
\"home-directory-listing\"<\/a><\/p>\n
That listing uses this mechanism to show the appropriate system icon for each file type.<\/p>\n
Furthermore, this feature is usable from regular web pages! Just put a “moz-icon” URL into an <image> tag and you’ll get OS-specific icons in your webpage.<\/p>\n
That’ll only work on Firefox, though. Chrome actually has a similar mechanism, though it’s not usable from regular web pages. (For more detail — much<\/em> more — read here<\/a>.) As far as I know Safari, IE and Edge do not have such a mechanism; I’m not sure if they support listing of local directories in this fashion.<\/p>\n","protected":false},"excerpt":{"rendered":"
Here’s an odd little feature in Firefox. Enter the following text into the address bar. moz-icon:\/\/.pdf?size=128 On my Linux box, it shows the following icon image. On my Windows laptop, it shows a different icon image. On my Mac Laptop, that URL doesn’t work but if I change the “128” to “64” it shows this […]<\/p>\n","protected":false},"author":139,"featured_media":0,"comment_status":"open","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[30],"tags":[],"_links":{"self":[{"href":"https:\/\/blog.mozilla.org\/nnethercote\/wp-json\/wp\/v2\/posts\/3113"}],"collection":[{"href":"https:\/\/blog.mozilla.org\/nnethercote\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/blog.mozilla.org\/nnethercote\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/blog.mozilla.org\/nnethercote\/wp-json\/wp\/v2\/users\/139"}],"replies":[{"embeddable":true,"href":"https:\/\/blog.mozilla.org\/nnethercote\/wp-json\/wp\/v2\/comments?post=3113"}],"version-history":[{"count":0,"href":"https:\/\/blog.mozilla.org\/nnethercote\/wp-json\/wp\/v2\/posts\/3113\/revisions"}],"wp:attachment":[{"href":"https:\/\/blog.mozilla.org\/nnethercote\/wp-json\/wp\/v2\/media?parent=3113"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/blog.mozilla.org\/nnethercote\/wp-json\/wp\/v2\/categories?post=3113"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/blog.mozilla.org\/nnethercote\/wp-json\/wp\/v2\/tags?post=3113"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}