请大神帮我看看，为何 arraysSimilar([,'3',4],[,3,4]) 弹出为true，好像是for in循环哪里出错了，改成普通for循环就没问题，求大神解答

源自：1-6 编程练习

<!DOCTYPE HTML>

<html>

<head>

<title>比较两个数组</title>

</head>

<body>

* param1 Array

* param2 Array

* return true or false

function type(a){

return a === null ? '[object Null]':Object.prototype.toString.apply(a); //hack ie678

}

function arraysSimilar(arr1, arr2){

if(arr1 instanceof Array && arr2 instanceof Array && arr1.length==arr2.length){

var arr11=[],arr22=[];

for(var i in arr1){

arr11.push(arr1[i]);

arr22.push(arr2[i]);

}

var arrs1=arr11.sort(),arrs2=arr22.sort(),ty1=[],ty2=[];

for(var i in arr1){

//alert( Object.prototype.toString.apply(arr1[i]))

ty1.push(type(arrs1[i]));

ty2.push(type(arrs2[i]));

}

// alert(ty1+'\n'+ty2)

var str1=arrs1.toString();

var str2=arrs2.toString();

var str3=ty1.toString();

var str4=ty2.toString();

if(str1==str2&&str3==str4){

return true

}else{return false}

}

alert(arraysSimilar([,'3',4],[,3,4]))

</script>

</body>

</html>

提问者：慕仙1417878 2017-12-20 13:48