# 3. Request payment
Once [**IMP object initialization**](/docs-en/auth/guide/2..md) is complete, you can open the payment window.
You can pass the [**parameters**](/docs-en/sdk/javascript-sdk.md) required to call the payment window in the first argument of the **request\_pay** function.
{% tabs %}
{% tab title="JavaScript" %}
```javascript
```
{% endtab %}
{% tab title="React.js" %}
```jsx
class RequestPay extends React.Component {
requestPay = () => {
IMP.request_pay({ // param
pg: "kcp",
pay_method: "card",
merchant_uid: "ORD20180131-0000011",
name: "Norway swivel chair",
amount: 64900,
buyer_email: "gildong@gmail.com",
buyer_name: "Hong Gildong",
buyer_tel: "010-4242-4242",
buyer_addr: "Shinsa-dong, Gangnam-gu, Seoul",
buyer_postcode: "01181"
}, rsp => { // callback
if (rsp.success) {
...,
// Payment is successful
...
} else {
...,
// Payment failed
...
}
});
}
```
{% endtab %}
{% tab title="Vue.js" %}
```javascript
```
{% endtab %}
{% endtabs %}
{% hint style="info" %}
**Note - Creating an order ID (merchant\_uid)**
* The order number must always be assigned a **unique** **value** when the payment window is requested.
* After the payment process is complete, the server uses the order ID to retrieve the order information for **payment fraud check**. Be sure to create a **unique ID** on the merchant server and **store it in the DB**.
{% endhint %}
#### The following is the above sample code with the Pay button added.
{% code title="sample.html" %}
```html
Sample Payment
```
{% endcode %}
{% embed url="" %}
Creating the Pay button for opening the payment window
{% endembed %}
{% embed url="" %}
Sample payment window
{% endembed %}
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