How to select a random element from array in JavaScript ?
The task is to select the random element from the array using JavaScript.
Approach 1:
- Use Math.random() function to get the random number between(0-1, 1 exclusive).
- Multiply it by the array length to get the numbers between(0-arrayLength).
- Use Math.floor() to get the index ranging from(0 to arrayLength-1).
Example: This example implements the above approach.
html
<body style="text-align:center;"> <h1 style="color:green;"> GeeksForGeeks </h1> <p id="GFG_UP" style="font-size: 15px; font-weight: bold;"> </p> <button id="button" onclick="GFG_Fun()"> click here </button> <p id="GFG_DOWN" style="font-size: 24px; font-weight: bold; color: green;"> </p> <script> var up = document.getElementById('GFG_UP'); var down = document.getElementById('GFG_DOWN'); var arr = ["GFG_1", "GeeksForGeeks", "Geeks", "Computer Science Portal"]; up.innerHTML = "Click on the button to check " + "the type of element.<br><br>" + arr; function GFG_Fun() { down.innerHTML = arr[Math.floor(Math.random() * arr.length)]; } </script></body> |
Output:
Approach 2:
- The random(a, b) method is used to generate a number between(a to b, b exclusive).
- Taking the floor value to range the numbers from (1 to arrayLength).
- Subtract 1 to get the index ranging from(0 to arrayLength-1).
Example: This example implements the above approach.
html
<body style="text-align:center;"> <h1 style="color:green;"> GeeksForGeeks </h1> <p id="GFG_UP" style="font-size: 15px; font-weight: bold;"> </p> <button id="button" onclick="GFG_Fun()"> click here </button> <p id="GFG_DOWN" style="font-size: 24px; font-weight: bold; color: green;"> </p> <script> var up = document.getElementById('GFG_UP'); var down = document.getElementById('GFG_DOWN'); var arr = ["GFG_1", "GeeksForGeeks", "Geeks", "Computer Science Portal"]; up.innerHTML = "Click on the button to select" + " random element from the" + " array.<br><br>" + arr; function random(mn, mx) { return Math.random() * (mx - mn) + mn; } function GFG_Fun() { down.innerHTML = arr[Math.floor(random(1, 5))-1]; } </script></body> |
Output:
JavaScript is best known for web page development but it is also used in a variety of non-browser environments. You can learn JavaScript from the ground up by following this JavaScript Tutorial and JavaScript Examples.
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