The concat method of the JavaScript Array object is used to create a new array from an array, while appending any arguments passed to the concat method to the array on which the concat method was called.
var aryTest = [1,2];
var aryNew = aryTest.concat(3);
document.write(aryNew);
The preceding example appends creates a new array from an existing array and appends the value 3 to it.
If an array is passed as one of the parameters to the concat method, that array is converted to a string and then added to the array on which that concat method was called. This is demonstrated in the following example:
var aryTest = [1,2];
var aryNew = aryTest.concat(3,[4,5]);
document.write(aryNew);
