javascript 千分位處理

Posted on 2020-04-03 Edited on 2023-11-24 In 前端特效 Views: Disqus:
先前工作需要，在網路上找到一篇在處理千分位的範例，
我也拿他的 code 來改，真是對我受益良多，
範例如下，之後有時間再來對其中的程式碼多做說明。
<!DOCTYPE html>
<html>

<head>
    <meta charset="utf-8">
    <meta name="viewport" content="width=device-width">
    <style>
        html {
            box-sizing: border-box;
        }

        *,
        *:before,
        *:after {
            box-sizing: inherit;
        }


        body {
            background: #f5f5f5;
            color: #333;
            font-family: arial, helvetica, sans-serif;
            font-size: 32px;
        }

        h1 {
            font-size: 32px;
            text-align: center;
        }

        p {
            font-size: 20px;
            line-height: 1.5;
            margin: 40px auto 0;
            max-width: 640px;
        }

        pre {
            background: #eee;
            border: 1px solid #ccc;
            font-size: 16px;
            padding: 20px;
        }

        form {
            margin: 40px auto 0;
        }

        label {
            display: block;
            font-size: 24px;
            font-weight: bold;
            margin-bottom: 10px;
        }

        input {
            border: 2px solid #333;
            border-radius: 5px;
            color: #333;
            font-size: 32px;
            margin: 0 0 20px;
            padding: .5rem 1rem;
            width: 100%;

        }

        button {
            background: #fff;
            border: 2px solid #333;
            border-radius: 5px;
            color: #333;
            font-size: 16px;
            font-weight: bold;
            padding: 1rem;
        }

        button:hover {
            background: #333;
            border: 2px solid #333;
            color: #fff;
        }

        .main {
            background: #fff;
            border: 5px solid #ccc;
            border-radius: 10px;
            margin: 40px auto;
            padding: 40px;
            width: 80%;
            max-width: 700px;
        }
    </style>
    <script src="https://cdnjs.cloudflare.com/ajax/libs/jquery/3.1.0/jquery.min.js"></script>
</head>

<body>
    <div class="main">
        <h1>Auto Formatting Currency</h1>

        <form method="post" action="#">
            <label for="currency-field">Enter Amount</label>
            <input type="text" name="currency-field" id="currency-field" pattern="^\$\d{1,3}(,\d{3})*(\.\d+)?$" value=""
                data-type="currency" placeholder="$1,000,000.00">
            <button type="submit">Submit</button>
        </form>

        <p>Auto format currency input field with commas and decimals if needed. Text is automatically formated with
            commas
            and cursor is placed back where user left off after formatting vs cursor moving to the end of the input.
            Validation is on KeyUp and a final validation is done on blur.</p>

        <p>To use just add the following to an input field:</p>

        <pre>data-type="currency"</pre>

    </div><!-- /main -->

    <script>
        // Jquery Dependency

        $("input[data-type='currency']").on({
            keyup: function () {
                formatCurrency($(this));
            },
            blur: function () {
                formatCurrency($(this), "blur");
            }
        });


        function formatNumber(n) {
            // format number 1000000 to 1,234,567
            return n.replace(/\D/g, "").replace(/\B(?=(\d{3})+(?!\d))/g, ",")
        }


        function formatCurrency(input, blur) {
            // appends $ to value, validates decimal side
            // and puts cursor back in right position.

            // get input value
            var input_val = input.val();

            // don't validate empty input
            if (input_val === "") { return; }

            // original length
            var original_len = input_val.length;

            // initial caret position 
            var caret_pos = input.prop("selectionStart");

            // check for decimal
            if (input_val.indexOf(".") >= 0) {

                // get position of first decimal
                // this prevents multiple decimals from
                // being entered
                var decimal_pos = input_val.indexOf(".");

                // split number by decimal point
                var left_side = input_val.substring(0, decimal_pos);
                var right_side = input_val.substring(decimal_pos);

                // add commas to left side of number
                left_side = formatNumber(left_side);

                // validate right side
                right_side = formatNumber(right_side);

                // On blur make sure 2 numbers after decimal
                if (blur === "blur") {
                    right_side += "00";
                }

                // Limit decimal to only 2 digits
                right_side = right_side.substring(0, 2);

                // join number by .
                input_val = "$" + left_side + "." + right_side;

            } else {
                // no decimal entered
                // add commas to number
                // remove all non-digits
                input_val = formatNumber(input_val);
                input_val = "$" + input_val;

                // final formatting
                if (blur === "blur") {
                    input_val += ".00";
                }
            }

            // send updated string to input
            input.val(input_val);

            // put caret back in the right position
            var updated_len = input_val.length;
            caret_pos = updated_len - original_len + caret_pos;
            input[0].setSelectionRange(caret_pos, caret_pos);
        }
    </script>
</body>

</html>
參考資料：
Auto Formatting Currency
{JavaScript}將數值增加千分位顯示與解除千分位
[Javascrpt]轉換數字成含千分位的文字