It is a best practice to wrap all React components in a single root element, like a <div>. By doing this we ensure that the component rendered is a single HTML element, as React expects its components to return a single element. Additionally, if multiple elements are returned we could easily encounter unexpected behaviors and hard-to-debug errors.

For example, when returning multiple elements from a component, React will wrap them in a <div> element and render them as a group. This can cause issues which can be difficult to identify, as your component might not be rendered as expected.

For example, let's say we have a component like the following in React:

jsx
 
 
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const MyComponent = () => {
    return (
        <h1>First Element</h1>
        <h2>Second Element</h2>
    );
};

This code won't render as expected as React will wrap the multiple HTML elements <h1> and <h2> in a single <div>.

To prevent this unexpected behavior and ensure that a single HTML element is always returned by our component, we should always wrap our components in a <div>. For example, the component should be written like this instead:

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const MyComponent = () => {
    return (
        <div>
            <h1>First Element</h1>
            <h2>Second Element</h2>
        </div>
    );
};

This would prevent any unexpected behavior and ensure that the component is rendered as expected.

More information can be found in the React docs.

The code is written in JavaScript and makes use of DOM-related functions, such as document.querySelector to access and manipulate elements of the DOM.

The search() function is being triggered when the user submits the form, indicated by the event listener form.addEventListener set to submit. The purpose of the function is to take the value from the input with the id="city-input" and store it. The event.preventDefault() is then used to actually prevent the form from submitting, since we want to manage the input with JavaScript logic first.

When the value is stored, a conditional is used to check whether the input is empty or not. If it is empty, an alert of the value will be triggered. Otherwise, the innerHTML of h5 is changed to the value of the input.

This is how the code works overall.

For more information on how events work in JavaScript, you can refer to this link.

CSS provides different properties for setting the margins of an element. To add a margin to an element, use the following property:

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margin: 10px;

This will give each side of the element 10px margin. You can also easily specify different margins for the top, right, bottom and left side of an element. For example,

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margin: 10px 30px 20px 5px;

The above code will give the element a margin of 10px on the top, 30px on the right, 20px on the bottom and 5px on the left.

More information and additional properties can be found here: MDN Documentation.

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function travel() {
    let name = prompt("What is your name?");
    let email = prompt("What is your email?");
    let travel = prompt("Do you enjoy traveling?");

    if (travel === "yes") {
        alert("Thank you " + name + "! I'll be in touch via email 😁");
    }
    else if (travel !== "yes") 
        alert("Thank you " + name + "! We won't bother you with emails at the moment, but if you change your mind, let us know!");
}

html
 
 
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<h1>Hello World</h1>