'use strict';

function get_primes(arr) {
   var filter_func = function(x){
      if(parseInt(x)==x && x>1){
        for(let i=2;i<=x/2;i++)
            {    
                 if(x%i){
                     continue;
                 }
                 else{
                 return false;
                 }
            }
        return true;
      }
      else{
        return false;
      }
   }    
   return arr.filter(filter_func);
}

// 测试:
var
    x,
    r,
    arr = [];
for (x = 1; x < 100; x++) {
    arr.push(x);
}
r = get_primes(arr);
if (r.toString() === [2, 3, 5, 7, 11, 13, 17, 19, 23, 29, 31, 37, 41, 43, 47, 53, 59, 61, 67, 71, 73, 79, 83, 89, 97].toString()) {
    alert('测试通过!');
} else {
    alert('测试失败: ' + r.toString());
}