How do I get the sum of three inputs values in a span using JavaScript or jQuery?

Question

I only have an only positive value for the input.

 var input = $('[name="1"],[name="2"],[name="3"]'), input1 = $('[name="1"]'), input2 = $('[name="2"]'), input3 = $('[name="3"]'), input4 = $('[name="4"]'); input.change(function() { var val1 = (isNaN(parseInt(input1.val())))? 0: parseInt(input1.val()); var val2 = (isNaN(parseInt(input2.val())))? 0: parseInt(input2.val()); var val3 = (isNaN(parseInt(input3.val())))? 0: parseInt(input3.val()); input4.val(val1 + val2 + val3); });

 <script src="https://ajax.googleapis.com/ajax/libs/jquery/3.5.1/jquery.min.js"></script> <input type="number" id="number1" name="1" min="0" max="8" value="0" /> <input type="number" id="number3" name="3" min="0" max="8" value="0" /> <input type="number" id="number2" name="2" min="0" max="8" value="0" /> <input type="number" id="number3" name="3" min="0" max="8" value="0" /> <span class="total-select" name="4">0</span>

How to get an answer at runtime (without any click to get an answer) in the span.

Answer 1

You can use each loop to iterate through your inputs and get required value from each inputs add them and then use $(".total-select").text(val); to same inside your span

Demo Code :

 $("input[type=number]").change(function() { var val = 0; //loop through each inputs $("input[type=number]").each(function() { //sum values val += parseInt($(this).val()) }) //put in span $(".total-select").text(val); });

 <script src="https://cdnjs.cloudflare.com/ajax/libs/jquery/3.3.1/jquery.min.js"></script> <input type="number" id="number1" name="1" min="0" max="8" value="0" /> <input type="number" id="number3" name="3" min="0" max="8" value="0" /> <input type="number" id="number2" name="2" min="0" max="8" value="0" /> <input type="number" id="number4" name="3" min="0" max="8" value="0" /> <span class="total-select" name="4">0</span>

Answer 2

Try this, your snippet have a many typo. use parseInt(input1.val())|0 to check and get a value, if value is NaN, then value = 0

 var input = $('[name="1"],[name="2"],[name="3"]'), input1 = $('[name="1"]'), input2 = $('[name="2"]'), input3 = $('[name="3"]'), input4 = $('[name="4"]'); input.change(function() { var val1 = parseInt(input1.val())|0; var val2 = parseInt(input2.val())|0; var val3 = parseInt(input3.val())|0; input4.html(val1 + val2 + val3); });

 <script src="https://cdnjs.cloudflare.com/ajax/libs/jquery/3.3.1/jquery.min.js"></script> <input type="number" id="number1" name="1" min="0" max="8" value="0" />+ <input type="number" id="number2" name="2" min="0" max="8" value="0" />+ <input type="number" id="number3" name="3" min="0" max="8" value="0" />= <span class="total-select" name="4">0</span>

Answer 3

Taking into account that you can obtain the sum of the numbers contained in an array using the Array.prototype.reduce method:

 const arr = [1, 2, 3, 4, 5]; const total = arr.reduce((sum, n) => sum + n, 0); console.log(total);

You could use the toArray jQuery method to convert the jQuery input selection to an array, and apply the same technique to get the result:

 const inputs = $('input[type="number"]'); const span = $('span[name="4"]'); inputs.on("change", () => { span.text( inputs.toArray().reduce((sum, item) => sum += (+item.value || 0), 0) ); });

 <script src="https://cdnjs.cloudflare.com/ajax/libs/jquery/3.3.1/jquery.min.js"></script> <input type="number" id="number1" name="1" min="0" max="8" value="0" /> <input type="number" id="number3" name="3" min="0" max="8" value="0" /> <input type="number" id="number2" name="2" min="0" max="8" value="0" /> <span name="4">0</span>