JavaScript | Add new elements at the beginning of an array
Adding new elements at the beginning of existing array can be done by using Array unshift() method. This method is similar to push() method but it adds element at the beginning of the array.
Syntax:
ArrayObject.unshift( arrayElement );
- ArrayObject: It is the array, where to insert the element.
- arrayElement: It is the element, which is to be inserted.
Example: This example inserts the element 6 at the beginning of array GFG_Array.
<!DOCTYPE html> <html> <head> <title> JavaScript | Insert at beginning </title></head> <body style = "text-align:center;"> <h1 style = "color:green;" > GeeksForGeeks </h1> <p id="up"></p> <button onclick="myGFG()"> Click to insert </button> <p id="down" style="color: green"></p> <!-- Script to add element at beginning of array --> <script> var GFG_Array = [1, 2, 3, 4, 5]; var up = document.getElementById("up"); up.innerHTML = GFG_Array; var down = document.getElementById("down"); down.innerHTML = "elements of GFG_Array = " + GFG_Array; function myGFG() { GFG_Array.unshift("6"); down = document.getElementById("down"); down.innerHTML = "element of GFG_Array = " + GFG_Array; } </script> </body> </html> |
Output:
- Before clicking the button:
- After clicking the button:
Example: This example inserts the element GFG_7 at the beginning of the GFG_Array.
<!DOCTYPE html> <html> <head> <title> JavaScript | Insert at beginning </title></head> <body style = "text-align:center;"> <h1 style = "color:green;" > GeeksForGeeks </h1> <p id="up"></p> <button onclick="myGFG()"> Click to insert </button> <p id="down" style="color: green"></p> <script> var GFG_Array = ["GFG_1", "GFG_2", "GFG_3", "GFG_4"]; var up = document.getElementById("up"); up.innerHTML = GFG_Array; var down = document.getElementById("down"); down.innerHTML = "elements of GFG_Array = " + GFG_Array; function myGFG() { GFG_Array.unshift("GFG_7"); down = document.getElementById("down"); down.innerHTML = "element of GFG_Array = " + GFG_Array; } </script> </body> </html> |
Output:
- Before clicking the button:
- After clicking the button:
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