无法检查输入是否有价值

Question

I want to loop through array of ids and check if value exists or not and do stuff code below:

function checkBillingFields() {

var inputIDS = [ "#billing_first_name", "#billing_last_name", "#billing_company", "#billing_phone", "#billing_address_1", "#billing_address_2", "#billing_city", "#billing_city"];

var arrayLength = inputIDS.length;

for (var i = 0; i < arrayLength; i++) {

    console.log(inputIDS[i]);

    if ($("inputIDS[i]").val().length == 0){

        $('.woocommerce-billing-fields__field-wrapper').appendTo('.billing-fields');

        $(".billing-heading").css({'margin-top': '100px'});

    }else{
        $(".expand-billing").css({'display': 'none'});
    }

}

}

checkBillingFields();

I get error Cannot read property 'length' of undefined. I use local storage to store inputs and it works fine tested.

Any ideas are helpful as I been researching and trying to fix that but nothing worked.

Answer 1

Replace your if statement with

if ($(inputIDS[i]).val().length == 0)

This will use jQuery directly with value from array and not with string literal as used in your case.

To really make sure you don't get any errors anymore, do it like this

//First check if element actually exists in DOM
var tmp = $(inputIDS[i]);
if (tmp.length == 1 && tmp.val().length == 0) {

}

Answer 2

Just like your console.log() use the same in your if statement

console.log(inputIDS[i]); 
if ($(inputIDS[i]).val().length == 0){

inputIDS[i] // returns #billing_first_name if i = 0
"inputIDS[i]" would return "inputIDS[i]"