Using JavaScript, you can call a function with an event listener by setting up the event listener on an element and then assigning a callback function to it. For example:

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const btn = document.querySelector("button");
btn.addEventListener("click", myFunction);

function myFunction(){
  console.log("Button clicked!");
}

In the above example, when the button element is clicked, it will call the function myFunction. For more info, see MDN Web Docs.

The logical AND operator in JavaScript is represented by &&. It is used to combine two or more conditions and returns true only if all conditions are true.

Here’s a simple example:

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let a = true;
let b = false;

console.log(a && b); // Output: false

In this example, a is true, and b is false. The expression a && b evaluates to false because both conditions need to be true for the result to be true.

You can learn more about it in the MDN web docs.

parseFloat is a built-in JavaScript function that converts a string into a floating-point number (a number that can have decimals). It's useful when you want to take a string that represents a number and turn it into a format that you can perform calculations with.

Here's how it works:

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let stringNumber = "3.14";
let floatNumber = parseFloat(stringNumber);

console.log(floatNumber); // Outputs: 3.14
console.log(typeof floatNumber); // Outputs: "number"

In this example, parseFloat takes the string "3.14" and converts it to the number 3.14. If the string doesn't start with a number, it will return NaN (which means "Not-a-Number").

For more information, you can check the MDN documentation on parseFloat.

In JavaScript, a break statement is used to stop the execution of a loop or switch statement. When the break statement is reached, the program will exit the loop or switch and continue with the next line of code after it.

Here’s a simple example with a loop:

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for (let i = 0; i < 10; i++) {
    if (i === 5) {
        break; // Exit the loop when i is 5
    }
    console.log(i);
}

In this example, the loop prints numbers from 0 to 4. When i becomes 5, the break statement is executed, and the loop ends.

You can learn more about break statements in JavaScript on MDN Web Docs.

In JavaScript, .push is a method used to add one or more elements to the end of an array. It modifies the original array and returns the new length of the array.

Here's a simple example:

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let fruits = ['apple', 'banana'];
fruits.push('orange'); // Adds 'orange' to the end of the array
console.log(fruits); // Output: ['apple', 'banana', 'orange']

You can find more information about the .push method in the MDN documentation.

console.log is a function in JavaScript that you can use to print messages or values to the console. This is helpful for debugging your code or checking the output of variables during development.

Here's a simple example:

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let greeting = "Hello, World!";
console.log(greeting);

In this example, when you run the code, it will display Hello, World! in the console. You can use console.log to display numbers, strings, and even objects or arrays.

For more details, you can check out the MDN Web Docs on console.log.

In JavaScript, the trim() method is used to remove whitespace from both ends of a string. This is useful when you want to clean up user input.

Here's how you can use it:

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let myString = "   Hello, World!   ";
let trimmedString = myString.trim();

console.log(trimmedString); // "Hello, World!"

In this example, trim() removes the spaces before "Hello," and after "World!" and gives us a clean string.

You can find more information about string methods in JavaScript here.

const is a keyword in JavaScript that is used to declare a variable whose value cannot be changed (or reassigned) after it is defined. It stands for "constant". This means that once you set a value to a variable using const, you cannot change that value later in the code.

Here's a simple example:

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const pi = 3.14;
console.log(pi); // Outputs: 3.14

// This line would cause an error because you cannot reassign a constant variable
// pi = 3.14159; // Uncaught TypeError: Assignment to constant variable.

For more information, you can check the MDN Web Docs on const.