Web Browsers as Programmable Calculators ...for those special calculations

Almost any scientific formula can be turned into a bookmarklet. Scientific formulas tend to be small in size (like bookmarklets), and since bookmarklets can be easily configured within your Bookmarks/Favorites they enable you to quickly set up a range of special-purpose calculators for temporary or frequent calculations. There are some advantages to using web browsers over traditional programmable calculators: Ease of programming - JavaScript is a fairly easy scripting language to learn (see below), and has other applications. Ease of distribution - If someone creates a bookmarklet which is a special-purpose calculator then they can distribute it through a webpage. The bookmarklet can be triggered while on the page or dragged into the Bookmarks/Favorites menu for permanent reuse. Cross-platform - Calculators tend to use the part of JavaScript which is common to both major browsers. Unlike the languages used by most programmable calculators, bookmarklets can be shared between browsers. Web browsers are free - most programmable calculators are expensive. For those who like to make bookmarklets, there are a vast number of useful formulas that are good candidates: the lack of a fancy interface doesn't keep a useful formula from being useful, and formulas tend to be in the public domain (as any good scientist can tell you.) To write a special-purpose calculator as a bookmarklet, study some of the examples in the Calculate/Convert section. You can get the "source" of a bookmarklet by copying the link location from the bookmarklet link, then paste it into a text editor and play with it. For example, here is the source of a simple version of a Download Calculator which roughly tells how long it will take to download a file of known size using a 28.8 modem:   javascript:     X=prompt('File size:','');     alert('At 28.8, the file will take about ' + X*1024*8/28800 + ' seconds to download.') Try it. Normally in a bookmarklet the script would all be on one line, but I've written this out on seperate lines for greater readability. The idea is quite simple: you just prompt for the input, then alert the output. Inside the alert you place a formula - in this case it's X*1024*8/28800, which converts between KiloBytes (which are used to describe file sizes) and Kilobits (used to describe transfer rates). As you study more examples, you learn more tricks: ways of handling errors, taking more than one input variable, making it easier to copy the output, and so on. But the crucial part is in knowing a good formula to start with. Once you've made a special-purpose calculator you can share it with others by making a link to it, just as you would with a webpage URL. Visitors to your page can keep the tool by pointing at the link and selecting "Add to Bookmarks/Favorites" from their (right-click) menu. (Macintosh/Unix users may have to rename the Bookmark after keeping it.) - Simple! If you come up with any good ones, or need some extra help, please let me know! Back