JavaScript类型转换问题

var arr = ['100px','abc'-6,[],-98977,34,-2,0,'300',,function(){alert(1);},null,
document,[],true,'200px'-30,'23.23元',5,Number('abc'),function(){alert(3);}];
//3、在这个数组中找到可以转换成数字的元素值:
function f3(){
for(var i=0;i<arr.length;i++){
if(){ //?????
console.log(arr[i]);
}
}
}
f3(); //结果应该为'100px',-98977,34,-2,0,'300',5

 var arr = ['100px','abc'-6,[],-98977,34,-2,0,'300',,function(){alert(1);},null,
document,[],true,'200px'-30,'23.23元',5,Number('abc'),function(){alert(3);}];
    //3、在这个数组中找到可以转换成数字的元素值:
    function f3() {
        for (var i = 0; i < arr.length; i++) {
            if (!isNaN(parseInt(arr[i]))) {
                console.log(arr[i]);
            }
        }
    }
    f3()

@ sinat_37181010 打广告的吧！