JSFiddle - React, Tailwind, and code Playground

HTML

<body>
<h1>Car Rental</h1>
    <form name="frmRental" method="post">
        Name:<br>
        <input type="text" name="txtName" size="20" maxlength="25"><br>
        Address:<br>
        <input type="text" name="txtAddress" size="20" maxlength="25"><br>
        City:<br>
        <input type="text" name="txtCity" size="20" maxlength="25"><br>
        State:<br>
        <input type="text" name="txtState" size="2" maxlength="2"><br>
        Zip:<br>
        <input type="text" name="txtZip" size="5" maxlength="5"><br>
        E-Mail Address:<br>
        <input type="email" name="txtEmail" size="20" maxlength="25"><br>
        Car Type:<br>
        <input type="text" name="txtCarType" size="20">
        <br>
        Pickup Date:
        <br>
        <input type="date" name="txtPickupDate" size="10">
        <br>
        Return Date:
        <br>
        <input type="date" name="txtReturnDate" size="10">
        <br><br>
        <input type="button" name="btnSave" value="Save Reservation" onClick="setCookies()"> 
        <input type="reset" value="Reset Form"> 
        <input type="button" name="btnRedisplay" value="Redisplay Reservation" onClick="displayCookies()">
    </form>

</body>

</html>

JavaScript

function setCookies()
		{
			// this function will set cookies for each field in the reservation form, and set them to expire after one day
			var Name = document.forms[0].txtName.value;
			var Address = document.forms[0].txtAddress.value;
			var City = document.forms[0].txtCity.value;
			var State = document.forms[0].txtState.value;
			var Zip = document.forms[0].txtZip.value;
			var Email = document.forms[0].txtEmail.value;
			var CarType = document.forms[0].txtCarType.value;
			var PickupDate = document.forms[0].txtPickupDate.value;
			var ReturnDate = document.forms[0].txtReturnDate.value;

			var myDate = new Date();
			myDate.setDate(myDate.getDate() + 7);
			
			document.cookie = "name=" + encodeURIComponent(Name) + "; expires=" + myDate.toUTCString();
			document.cookie = "address=" + encodeURIComponent(Address) + "; expires=" + myDate.toUTCString();
			document.cookie = "city=" + encodeURIComponent(City) + "; expires=" + myDate.toUTCString();
			document.cookie = "state=" + encodeURIComponent(State) + "; expires=" + myDate.toUTCString();
			document.cookie = "zip=" + encodeURIComponent(Zip) + "; expires=" + myDate.toUTCString();
			document.cookie = "email=" + encodeURIComponent(Email) + "; expires=" + myDate.toUTCString();
			document.cookie = "carType=" + encodeURIComponent(CarType) + "; expires=" + myDate.toUTCString();
			document.cookie = "pickupDate=" + encodeURIComponent(PickupDate) + "; expires=" + myDate.toUTCString();
			document.cookie = "returnDate=" + encodeURIComponent(ReturnDate) + "; expires=" + myDate.toUTCString();

			window.alert ("Your reservation has been saved.");
			
		} // end function setCookies()
		
		function displayCookies()
		{
			// this function will read the saved cookies, and repopulate the form with the cookie values
			
			var cookieString = decodeURIComponent(document.cookie);
			var cookieArray = cookieString.split("; ");
			console.log(cookieArray)
			if (document.cookie == 0)
			{
				alert("You have not made a...