JavaScript version of randomisation demo for the James Lind Library website - http:https://www.jameslindlibrary.org/

Originally commissioned by Sir Iain Chalmers and created by Jim Halsey and Chris Bird at CTSU, Oxford

* Assign to "Duration of health problem:"
    Long term (30% probability)
    More recent (70% probability)
* Assign to "Severity of health problem:"
    Mild  (30% probability)
    Moderate  (45% probability)
    Severe  (25% probability)
* Assign to "Age, in years"
    Under 15 (20% probability)
    15-34  (25% probability)
    35-64  (25% probability)
    65 & older  (30% probability)
* Assign to "Condition: Very anxious?"
    Yes (5% probability)
    No (95% probability)

make style consistent with site, e.g. http:https://www.jameslindlibrary.org/essays/2-2-the-need-to-compare-like-with-like-in-treatment-comparisons/

could turn function Factors() into var factors = new Array() and make multi-dim - then factor out function fillBase(factors) function fillNext(factors)

global vars bad, wrap in IIFE? http:https://stackoverflow.com/questions/2613310/ive-heard-global-variables-are-bad-what-alternative-solution-should-i-use

use TypeScript?

use WebPack?

percentages not shown

"back to beginning" doesn't work

after "Number of patients must be between 0 and 100,000" out-of-range alert, "next" values disappear