js 两个数组相减

var arr1 = ["", "120", "125", "125", "130", "130", "130", "130", "130"];

var arr2 = ["", "120", "125", "130"];

for (var i = arr1.length - 1; i >= 0; i--) {
    a = arr1[i];
    for (var j = arr2.length - 1; j >= 0; j--) {
        b = arr2[j];
        if (a == b) {
            arr1.splice(i, 1);
            arr2.splice(j, 1);
            break;
        }
    }
}

console.log(arr1);  // ["125","130","130","130","130"]