错误未捕获的错误：语法错误，表达式无法识别

Question

<div class="mt-repeater-item">
    <div class="row mt-repeater-row">
        <input type="text" name="product[0][price]" value="2" oninput="update_total(this)">
    </div>
</div>
<div class="mt-repeater-item">
    <div class="row mt-repeater-row">    
        <input type="text" name="product[1][price]" value="3" oninput="update_total(this)">
    </div>
</div>

And my script

function update_total(input) {
    var sum = 0;
    $('.mt-repeater-item').each(function(index) {
        var product_price = $("input[name=product["+index+"][price]]").val() ? $("input[name=product["+index+"][price]]").val() : 0;
        sum = sum + product_price;
    });
    alert(sum);
}

Error Uncaught Error: Syntax error, unrecognized expression => How to fix it?

Answer 1

function update_total(input) {
    var sum = 0;
    $('.mt-repeater-item').each(function(index) {
            var product_price = $("input[name='product["+index+"][price]']").val() ? $("input[name='product["+index+"][price]']").val() : 0;
        sum = sum + parseInt(product_price);
    });
    alert(sum);
}

enclose value of name inside single quotes

Answer 2

You have missing quotation for name --

function update_total(input) {
    var sum = 0;
    $('.mt-repeater-item').each(function(index) {
        var product_price = $("input[name='product["+index+"][price]']").val() ? $("input[name='product["+index+"][price]']").val() : 0;
        sum = sum + product_price;
    });
    alert(sum);
}

Link - https://jsfiddle.net/80op2y19/