Promise Based Bootstrap Modal As Confirmation Box or Alert.

alert.js

function bsPopup(title = 'Alert', msg = 'Are you sure?') {
        return new Promise((resolve, reject) => {
            const autoId = 'modal' + new Date().getTime();
            const modal = `
            <div class="modal fade" id="${autoId}" tabindex="-1">
            <div class="modal-dialog modal-dialog-centered" role="document">
                <div class="modal-content">
                    <div class="modal-header">
                        <h5 class="modal-title"><i class="fa fa-exclamation-triangle mr-1"></i> ${title}</h5>
                        <button type="button" class="close" data-dismiss="modal" aria-label="Close">
                            <span aria-hidden="true">&times;</span>
                        </button>
                    </div>
                    <div class="modal-body">${msg}</div>
                    <div class="modal-footer">
                        <button type="button" class="btn btn-secondary modal-cancel" data-dismiss="modal">CANCEL</button>
                        <button type="button" class="btn btn-primary modal-ok">OK</button>
                    </div>
                </div>
            </div>
            </div>`;
            $('body').append(modal);
            let modalElem = $("#" + autoId);
            modalElem.modal('show');
            modalElem.on('hidden.bs.modal').click((e) => {
                modalElem.remove();
                $('.modal-backdrop').remove();
                $('body').removeClass("modal-open");
                reject(false);
            });
            modalElem.find(".modal-ok").click(() => {
                modalElem.remove();
                $('.modal-backdrop').remove();
                $('body').removeClass("modal-open");
                resolve(true);
            });
        });
    }

    function confirmPrompt(event) {
        if(!event.isTrusted) return true;
        event.preventDefault();
        bsPopup().then(rs=>{
            if(rs) {
                event.target[event.type]();
            }
        });
        return false;
    }

index.html

<!--How to use-->
<a onclick="confirmPrompt(event)" href="google.com">test</a>
<form action="" onsubmit="return confirmPrompt(event)">
    <button type="submit">submit</button>
</form>

Full Example: https://jsfiddle.net/vwhpcuoe/