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JavaScript JavaScript Basics Storing and Tracking Information with Variables Change the Value in a Variable

Forrest Pollard
Forrest Pollard
1,988 Points

Cannot seem to correctly change the value of a variable from a prompt

Was experimenting with what i learned from this lesson by trying to do something myself but I am struggling. here is my code, i think you will understand what I have been trying to do,

var score = 0;
score += 10, score +=5;
var bonusPoints = 0;
bonusPoints += prompt("input desired bonus points");
score += bonusPoints;

however it keeps adding whatever is input in the prompt as a string at the end of the score value. Any help is greatly appreciated, many thanks :)

1 Answer

Austin Whipple
Austin Whipple
29,725 Points

Hi Forrest,

By default, the value submitted to the prompt you're displaying is going to be stored as a string. Using += is going to produce strange results using anything that's not an integer. Luckily, JavaScript has some handy functions to convert strings to integers/numbers! I suspect you can use parseint() without much problem, but perhaps Number() would work as well. Here's a StackOverflow article with lots more information.