Here's the code I used to get the answer (originally at least; now I'm using someone else's Sieve of Eratosthenes code from StackOverflow!):
/*
Find the summation of primes (Euler Problem 10)
This solution takes about 30sec to run. I don't really
understand the Sieve of Eratosthenes so I could only copy one of the
solutions on Stack Overflow... This solution works and it was mine.
*/
$(document).ready( function() {
function isPrime(n) {
if (n === 1) { return false;}
if (n === 2) { return true; }
var sqrt_n = Math.round(Math.floor(Math.sqrt(n)));
for (var i=2; i<=sqrt_n + 1; n++) {
if (n % i === 0) { return false; }
return true;
}
}
var sum = 2;
var limit = 2e+6;
for (var i=3; i<=limit; i+=2) {
if (isPrime(i)===true) { sum+=i; }
}
console.log(sum);
$("#output").text("Sum is " + sum );
});