npm i vant -S # 安裝最新版
npm i vant@latest-v2 -S # vue2項目，安裝vant2

<link rel="stylesheet"  rel="external nofollow" />
<script src="https://cdn.jsdelivr.net/npm/vant@2.12/lib/vant.min.js"></script>

 <script src="https://staticweb.keepcdn.com/fecommon/package/vant@2.8.7/vant/vant.min.js"></script>
<link rel="stylesheet"  rel="external nofollow" >

<label>價格：</label>
<input type="text" v-model.trim="price" inputmode="decimal" placeholder="請輸入價格" @keyup="handlePrice(price)"/>

<van-field type="number" v-model.number="price" label="價格" placeholder="請輸入價格" @keyup="handlePrice(price)"/>

handlePrice(val){
                if (val !== '' && val.substr(0, 1) === '.') {
                    val = "";
                }
                val = val.replace(/^0*(0\.|[1-9])/, '$1');//解決 粘貼不生效
                val = val.replace(/[^\d.]/g, "");  //清除“數(shù)字”和“.”以外的字符
                val = val.replace(/\.{2,}/g, "."); //只保留第一個. 清除多余的
                val = val.replace(".", "$#$").replace(/\./g, "").replace("$#$", ".");
                val = val.replace(/^(\-)*(\d+)\.(\d\d).*$/, '$1$2.$3');//只能輸入兩個小數(shù)
                if (val.indexOf(".") < 0 && val !== "") {
                    if (val.substr(0, 1) === '0' && val.length === 2) {
                        val = val.substr(1, val.length);
                    }
                }
                this.priceAll = this.priceOne = val;
            },