最近两次在牛客做网易的编程题，用JS写总是报错，有木有好心的大神帮我看看错哪了？

题一：奇怪的表达式求值

function fn(str){
    var len = str.length;
    var i = 0, output = 0;
    var num = [], op = [];
    str.replace(/(\d+)/g,function(a){
        num.push(a);
    });
    str.replace(/[+|-|*]/g,function(a){
        op.push(a);
    })
    var a, b, o;
    while(op.length>0){
        a = num.shift();
        b = num.shift();
        o = op.shift();
        output = eval(a+o+b);
        num.unshift(output);
    }
    return output;
}
function main(){
  var str = '11+5*100';
  console.log(fn(str));
}
main();

题二：忘记具体题目了，好像是集合，也是报内部错误，心好累T T

function fn(w,x,y,z){
    if(!(w>=1&&x>=1&&w=1&&1<=z&&z<=100&&y<=z))
        return 0;
    var i = 0, j = 0, obj = {},tmp=0;
    for(i=w;i<=x;i++){
        for(j=y;j<=z;j++){
            tmp = i/j;
            obj[tmp]=1;
        }
    }
    var output = 0;
    for(var item in obj){
        output++;
    }
    return output;
}
console.log(fn(1,10,1,1));