Calling JavaScript from component template

I’m working on integrating payment forms from a third party, by using the Link to Javascript they provide.

when I place the code in the index.html page its works just fine, but when I move the code to the component template is not working, below is part of the code:

this is the script code to initialize the payment form:

<script>
    var tokenpay = TokenPay('tokenpay123');

    tokenpay.initialize({
        dataElement: 'card',
        errorElement: 'errorMessage',
        amountElement: 'amount',
        useACH: false,
        //if displaying all 4 fields then useStyles=false, disableZip=false, disableCvv=false
        //if displaying 3 out of 4 fields then useStyles=false, and set disableZip or disableCvv equal to true
        //if displaying 2 out of 4 fields then useStyles=true, disableZip=true, disableCvv=true
        useStyles: false,
        disableZip: true,
        disableCvv: false
    });
    var form = document.getElementById('paymentForm');
    form.addEventListener('submit', function(event) {
        event.preventDefault();
        tokenpay.createToken(function(result) {
            alert(result.token)
        }, function(result) {
            console.log("error: " + result);
        });
    });
</script>

  <script type="text/javascript" src="http://xxx/tokenPay.js"></script>
 <form id="paymentForm" action="xxx" method="post" style="margin: 10%;">
       
        <div id="card" style="border: solid 1px lightgray; height: 100px; width: 500px; padding: 20px 10px; border-radius: 10px; margin: 10px 0px;">
        </div>
        <div id="errorMessage" style="margin-bottom: 10px; color: #c0392b;"></div>
        <button type="submit" class="btn btn-default">Submit</button>
        
    </form>

when I’m using these three-part together on the index page is working fine when I’m trying to work from a component template that is not

Answer

Put the script tag <script type="text/javascript" src="http://xxx/tokenPay.js"></script> inside the head tag within index.html

Then put the var tokenpay = TokenPay('tokenpay123'); etc block inside ngAfterViewInit within the relevant component (i.e. the component hosting the form). Then it should work fine.

Note that because tokenPay is a global variable, the TypeScript compiler will not recognise it so you will need to add:

declare const tokenPay: any

inside the .ts file of the relevant component.