+ 8

Why the output is 33 not 6?

When Sum button is clicked, alert Window will appear. https://code.sololearn.com/WuTa4N7pOT71/?ref=app

input value js sum number?string?

27th Dec 2018, 4:43 AM

Muhd Khairul Amirin

22 Answers

+ 4

https://code.sololearn.com/W0uk4VD12ALx/?ref=app

27th Dec 2018, 5:07 AM

ShortCode

+ 4

Best way to debug this code is checking type of things you are adding. Add following code to your function console.log(typeof(a)); console.log(typeof(b)); This tells a and b are string so they concatenate. So you are actually doing this "3"+"3"=33. Solution: coerce (change to another data type) those two inputs that are initially string type into number type by using parseInt() function.

27th Dec 2018, 5:09 AM

Prathamesh Sawant

+ 4

Because you added it.

28th Dec 2018, 9:51 AM

Sandakan Nipunajith

+ 3

Try var sum=+a+ +b;

27th Dec 2018, 5:12 AM

Calviղ

+ 3

Thanks everyone😄

27th Dec 2018, 9:34 AM

Muhd Khairul Amirin

+ 3

best practice in JS is still parseInt see https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Number/parseInt

27th Dec 2018, 12:30 PM

Claude Martin

+ 3

Looks like someone had downvoted this questions as well as its answers. 😓

28th Dec 2018, 3:51 AM

Muhd Khairul Amirin

+ 3

You need to convert a and b to numbers otherwise you're just concatenating two strings together.

28th Dec 2018, 5:21 PM

Dave David

+ 3

The value is retrieved as a string that's why

14th Feb 2019, 1:59 AM

👑 Prometheus 🇸🇬

+ 2

Calvin is it really good practice using that?

27th Dec 2018, 5:53 AM

Prathamesh Sawant

+ 2

The Learner the reason why your code has an error is caused when you try to add a 'addEventListener' method to the input tag with id 'cal'. When you do this the input tag with id 'cal' doesn't exist yet, the body hasn't loaded it and it's children, but your javascript is trying to get the values regardless and so null is returned for the variable cal. What you should do is run the javascript after all the elements that you need in the html have loaded. <body onload="onloadMethod();"> </body> function onloadMethod(){ Initialise all variables in here }

28th Dec 2018, 10:18 PM

Dave David

+ 2

♣Dave♠David♣ Yeah at least I'm gonna see the result with that ... thanks for help though 😄

28th Dec 2018, 10:30 PM

Edwing123

+ 2

The Learner Ive fixed some of your bug. https://code.sololearn.com/WKdwfdR885Pw/?ref=app

28th Dec 2018, 11:23 PM

ShortCode

+ 2

ShortCode 😊 thank you

28th Dec 2018, 11:29 PM

Edwing123

+ 1

Hahaha funny tricky fact about input type ="number", they are still string

28th Dec 2018, 9:43 PM

Edwing123

+ 1

If you wanna prevent user to use letter or any other character but not a number you can use the isNaN function, I found it useful with my code: https://code.sololearn.com/WnLYR0lI6Ez6/?ref=app Note: if somebody sees my code plz tell me why is showing me that error !! :)

28th Dec 2018, 9:47 PM

Edwing123

+ 1

♣Dave♠David♣ but why in my computer works? edited: not SL but in my local or if I open it in a browser.

28th Dec 2018, 10:22 PM

Edwing123

+ 1

The Learner i'm sorry i don't understand

28th Dec 2018, 10:23 PM

Dave David

+ 1

♣Dave♠David♣ well ... I created the code in my computer but not directly in Sololearn ... I created in brackets text editor, the page resulted ok everything. working.. but two days ago I uploaded to SL and it shows me that error ....

28th Dec 2018, 10:26 PM

Edwing123

+ 1

Remove value=3 in both places and run the code

30th Dec 2018, 4:41 PM

Madhuri