# Sum and Product of Array elements using JavaScript

• Last Updated : 12 Sep, 2019

Given an array and is the task to find the Sum and Product of the values of an Array using JavaScript.

Simple method: It uses a simple method to access the array elements by an index number and use the loop to find the sum and product of values of an Array using JavaScript.

Example 1: This example uses a simple method to find the sum of Array elements using JavaScript.

 ```<``html``>`` ` `<``head``>``    ``<``title``>``        ``How to Find the sum of Values``        ``of an Array in JavaScript?``    `````` ` `<``body` `style``=``"text-align:center;"``>``     ` `    ``<``h1` `style` `= ``"color:green;"` `> ``        ``GeeksForGeeks ``    `` ``     ` `    ``<``h3``>``        ``How to Find the sum of Values``        ``of an Array in JavaScript?``    ````     ` `    ``<``h4``>``        ``----Given Array----<``br``>``        ``[1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11]``    ````     ` `    ``<``button` `onclick``=``"myFunction()"``>Click``     ` `    ``<``p` `id``=``"gfg"``>``     ` `    ``<``script``>``        ``\$(document).ready(function() {``            ``\$("button").click(function() {``                ``function sum(input) {``                    ``if (toString.call(input) !== "[object Array]")``                    ``return false;``                     ` `                    ``var total = 0;``                    ``for(var i=0;i<``input.length``;i++) {                 ``                        ``if(isNaN(input[i])) {``                            ``continue;``                        ``}``                         ` `                        ``total += Number(input[i]);``                    ``}``                    ``return total;``                ``}``                ``document.getElementById("gfg")``.innerHTML``                        ``= ``"----Sum of Array----"` `+ "
"``                        ``+ sum([1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11]);``            ``});``        ``});``    `````` ` `              `

Output:

• Before click on the Button:
• After Click on the Button:
• Example 2: This example uses a simple method to find the product of Array elements using JavaScript.

 ```<``html``>`` ` `<``head``>``    ``<``title``>``        ``How to Find the product of Values``        ``of an Array in JavaScript?``    `````` ` `<``body` `style``=``"text-align:center;"``>``     ` `    ``<``h1` `style` `= ``"color:green;"` `> ``        ``GeeksForGeeks ``    `` ``     ` `    ``<``h3``>``        ``How to Find the product of Values``        ``of an Array in JavaScript?``    ````     ` `    ``<``h4``>``        ``----Given Array----<``br``>``        ``[1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11]``    ````     ` `    ``<``button` `onclick``=``"myFunction()"``>Click``     ` `    ``<``p` `id``=``"gfg"``>``     ` `    ``<``script``>``        ``\$(document).ready(function(){``            ``\$("button").click(function(){``                ``function product(input) {``                    ``if (toString.call(input) !== "[object Array]")``                    ``return false;``                 ` `                    ``var total = 1;``                    ``for(var i=0;i<``input.length``;i++) {                 ``                        ``if(isNaN(input[i])){``                            ``continue;``                        ``}``                     ` `                        ``total *= Number(input[i]);``                    ``}``                    ``return total;``                ``}``                ``document.getElementById("gfg")``.innerHTML``                    ``= ``"----product of Array----"` `+ "
" ``                    ``+ product([1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11]);``            ``});``        ``});``    `````` ` `      `

Output:

• Before click on the Button:
• After Click on the Button:

Using reduce() method: The array reduce() method in JavaScript is used to reduce the array to a single value and executes a provided function for each value of the array (from left-to-right) and the return value of the function is stored in an accumulator.

Syntax:

`array.reduce( function( total, currentValue, currentIndex, arr ), initialValue )`

Example 1: This example uses array reduce() method to find the sum of values of an Array using JavaScript.

 ```<``html``>`` ` `<``head``>``    ``<``title``>``        ``How to Find the sum of Values``        ``of an Array in JavaScript?``    `````` ` `<``body` `style``=``"text-align:center;"``>``     ` `    ``<``h1` `style` `= ``"color:green;"` `> ``        ``GeeksForGeeks ``    `` ``     ` `    ``<``h3``>``        ``How to Find the sum of Values``        ``of an Array in JavaScript?``    ````     ` `    ``<``h4``>``        ``----Given Array----<``br``>``        ``[1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11]``    ````     ` `    ``<``button` `onclick``=``"myGeeks()"``> ``        ``Click Here! ``    ````     ` `    ``<``br``><``br``>``     ` `    ``Sum: <``span` `id``=``"GFG"``> ``     ` `    ``<``script``>``        ``var arr=[1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11];``         ` `        ``function sumofArray(sum, num) { ``            ``return sum + num; ``        ``} ``        ``function myGeeks(item) { ``            ``document.getElementById("GFG").innerHTML ``                ``= arr.reduce(sumofArray); ``        ``} ``    `````` ` `        `

Output:

• Before click on the Button:
• After Click on the Button:

Example 2: This example uses array reduce() method to find the product of values of an Array using JavaScript.

 ```<``html``>`` ` `<``head``>``    ``<``title``>``        ``How to Find the product of Values``        ``of an Array in JavaScript?``    `````` ` `<``body` `style``=``"text-align:center;"``>``     ` `    ``<``h1` `style` `= ``"color:green;"` `> ``        ``GeeksForGeeks ``    `` ``     ` `    ``<``h3``>``        ``How to Find the product of Values``        ``of an Array in JavaScript?``    ````     ` `    ``<``h4``>``        ``----Given Array----<``br``>``        ``[1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11]``    ````     ` `    ``<``button` `onclick``=``"myGeeks()"``> ``        ``Click Here! ``    ````     ` `    ``<``br``><``br``>``     ` `    ``Product: <``span` `id``=``"GFG"``> ``     ` `    ``<``script``>``        ``var arr=[1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11];``         ` `        ``function productofArray(product, num) { ``            ``return product * num; ``        ``} ``        ``function myGeeks(item) { ``            ``document.getElementById("GFG").innerHTML ``                    ``= arr.reduce(productofArray); ``        ``} ``    `````` ` `         `

Output:

• Before click on the Button:
• After Click on the Button:

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