Seeking a statistical javascript function to return p-value from a z-score

Question

I need to convert z-scores to percentile. I found reference to a function in the jStat library that I could use (jstat.ztest), but the jStat documentation seems to be ahead

Answer 1

Just editing the code from Paul's answer for a two-sided t-test

function GetZPercent(z) 
{
//z == number of standard deviations from the mean

//if z is greater than 6.5 standard deviations from the mean
//the number of significant digits will be outside of a reasonable 
//range
if ( z < -6.5)
  return 0.0;
if( z > 6.5) 
  return 1.0;

if (z > 0) { z = -z;}

var factK = 1;
var sum = 0;
var term = 1;
var k = 0;
var loopStop = Math.exp(-23);
while(Math.abs(term) > loopStop) 
{
  term = .3989422804 * Math.pow(-1,k) * Math.pow(z,k) / (2 * k + 1) / Math.pow(2,k) * Math.pow(z,k+1) / factK;
  sum += term;
  k++;
  factK *= k;

}
sum += 0.5;

return (2*sum);
}