ha_permissions/ui/login/index.js

export default {
    form: null,

    display(){
        if(this.form === null){
            this.form = document.querySelector("#loginPage form");
            this.form.addEventListener("submit", (event)=>{
                this.submit(event);
            });
        }

        document.getElementById("loginPageEmail").focus();
    },

    async submit(event){
        event.preventDefault();

        const body = {
            email: document.getElementById("loginPageEmail").value,
            password: document.getElementById("loginPagePassword").value
        };

        const response = await fetch("/login", {
            method: "POST",
            headers: {"Content-Type": "application/json"},
            body: JSON.stringify(body)
        });
        
        const data = await response.json();
        if(!response.ok) return notify("error", data.msg);

        openPage("dashboard");
    }
}