console 命令行工具 X clear

console

function sumBig(a,b){
  var res='',c=0;
  a = a.split('');
  b = b.split('');
  
  while(a.length || b.length ||c){
    c += ~~a.pop() + ~~b.pop();
    res = c%10 + res;
    c = c>9;
  }
  
  return res.replace(/^0+/,'');
}

console.log(sumBig('12121212','323545456'));

<p>两个大数相加</p>