JS produces 20-bit random number to 0-9 as an example can also be a-Z a-z_javascript tips

JS Code:

function S20 () { 
var data=["0", "1", "" 2 "," 3 "," 4 "," 5 "," 6 "," 7 "," 8 "," 9 "," a "," B "," C "," D "," E "," F "]; 
for (Var j=0;j<500;j++) {//500 The number of rows to be generated
var result= "";
for (Var i=0;i<20;i++) {///Generate 20 bits to make i<20
R=math.floor (Math.random () *16);//16 the number of data in the array, the purpose is to use this moment to mark the value in the arrays! 
Result+=data[r]//output 20 times random number at the same time, let RRR add 20 times, is 20 bit of random string. 
} 
document.write (result); 
document.write ("<br/>"); 
} }

Full HTML code: