Many of the calculating web pages listed on the StatPages.net site utilize JavaScript programming, and HTML Forms fields. Both of these facilities contain certain idiosyncracies that you should be aware of as you interact with these pages.
The most important "fact of life" when dealing with JavaScript is that it behaves differently on different platforms (Mac vs. Windows PCs vs. Unix, etc.). It's not supposed to do that, but (at the present time) it does. So things that work fine on one platform may not work properly on another. Since I cannot debug every page on every platform, there will be some glitches. If you encounter something that doesn't work, please send me an e-mail message describing the problem (and what computer, operating system, browser, and version you were using), and I'll make every effort to fix the problem.
Even on a single platform, different web browsers (and even different versions of the same browser) don't always implement JavaScript exactly the same way. Some very old versions of Netscape (prior to v2) and Microsoft Internet Explorer (prior to v3) do not support JavaScript at all.
First, you will notice that the page contains certain fields into which you are expected to type in values.
One thing you should be aware of is that Web forms send data back to the host computer (Web server) if you press the Return or Enter key. But in pages that use JavaScript to do the calculations, we don't want to send data back to a host; all the necessary programming is already included in the web page, and all statistical computations are done entirely on your own computer.
Therefore, never press the Return or Enter key. You will move from field to field by pressing the Tab key, and you will initiate calculations by clicking on a button that usually has a name like Compute, or Calculate, or something similar. (In some of my web pages, a calculation will be performed automatically when you tab out of a field.)
I've found that it's often safest not to try to make alterations to part of an existing field (like selecting a single digit and changing it), but rather to re-type the entire field.
We've all been taught that leading zeros (extra zeros placed in front of a number) are optional, and don't alter the value of the number. That is, we know that 23 is numerically the same as 023. But in some versions of JavaScript, an integer (a whole number) with a leading zero will be interpreted as an octal constant (that is, a number written in base-8 notation).
So, as incredible as it may seem, many browsers will interpret the number 023 typed into a cell as having a numerical value of nineteen ! ! ! (That's because 2*8 + 3*1 equals 19.) The browser will give you no warning of this crazy behavior, only wrong results. As if this were not insane enough, those same browsers will correctly interpret the number 029 typed into a cell as having the numerical value of 29. (This is because the octal numbering system does not have the digit "9", therefore the browser interprets 029 as a decimal number.)
In my humble opinion, this inconsistent and dangerous behavior represents an unbelievably stupid design decision on the part of the JavaScript's creators. Fortunately, some versions of JavaScript have dropped this "leading zero implies octal, maybe" policy, but unfortunately the versions used in the current Internet Explorer and Firefox browsers still behave this way. So, never enter whole numbers with leading zeros. (Fractional numbers, like 0.23 can, and should, have one leading zero.)
I have tried to program the pages so that the field-tabbing sequence will be intuitive, skipping over output fields, cycling back to the first field, etc. Unfortunately, the current version of JavaScript does not always implement these commands exactly the same way on different platforms. So you might find that you have tabbed into an output field. If this happens, just double-click the field you want to enter data into.
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