Javascript Array object unshift () method, arrayunshift

Javascript Array object unshift () method, arrayunshift

The unshift () method can add one or more elements to the beginning of an array and return a new length.

ArrayObject. unshift (newelement1, newelement2,..., newelementX)
Newelement1 is required. The first element added to the array.
Newelement2 is optional. The second element added to the array.
NewelementX is optional. You can add several elements.
The unshift () method inserts its parameters into the arrayObject header, and sequentially moves existing elements to a higher subscript to leave space.
The first parameter of this method will be the new element 0 of the array. If there is a second parameter, it will become the new element 1, and so on.
The unshift () method directly modifies the original array instead of creating a new one. This method changes the length of the array. Method to return the new length of the arrayObject.
Note: The unshift () method cannot work correctly in Internet Explorer!

Tip: to add one or more elements to the end of the array, use the push () method.

Instance
Create an array, add an element to the beginning of the array, and return the new length of the array:

<Script type = "text/javascript"> var arr = new Array () arr [0] = "George" arr [1] = "John" arr [2] = "Thomas" document. write (arr + "<br/>") document. write (arr. unshift ("William") + "<br/>") document. write (arr) </script>

Output:

George, John, Thomas
4
William, George, John, Thomas