Changing value of JS variable depending on HTML button selected?

Question

Hi guys so i am trying to change the value of a javascript variable depending on what button is selected. For example

<button id="1" onclick="changeVal('val1')">b1</button>
<button id="2" onclick="changeVal('val2')">b2</button>

<script>
var value;
function changeVal(choice) {
  if (choice == 'val1') {
    value = 'number value 1'
  } else if (choice == 'val2'){
    value ='number value 2'
  }
*etc for more buttons*
}
</script>

The variable value will then be used later on. Can't really wrap my head around the problem, im either doing it completely wrong or so close but can't quite get there.

edit: So still having trouble, basically i want to return that choice value so it can then be called in another function e.g.

<script>
var value... 
function changeval... //Return choice value out

function useValue() {
    alert(choice) //Use choice value here
}

note ignore syntax wrote quickly.

What is the problem here exactly? Is the value variable not assigned to the value that you want? — Naz Ekin
– Naz Ekin, Commented Aug 21, 2016 at 16:19
@biseibutsu so im using the variable later on in another function, but it doesn't seem to run, is my code above correct? If so it means my issue is with my other function, but that is GIS openlayers related so will have to post there. — cmca
– cmca, Commented Aug 21, 2016 at 16:27
From what you have posted this code should work, but I cannot say for sure since I dont know where it doesn't run. — Naz Ekin
– Naz Ekin, Commented Aug 21, 2016 at 16:28
@biseibutsu ok thanks, i have left my computer so can't post specific openlayers script. But will give it a try tomorrow morning and update you. — cmca
– cmca, Commented Aug 21, 2016 at 16:35

The SuperKat · Accepted Answer · 2016-08-21 17:04:49Z

1

The above code runs perfectly in a web browser. The problem must be with the concept of variable scope. Or in the function you are using the value variable.

answered Aug 21, 2016 at 17:04

The SuperKat

2343 silver badges11 bronze badges

Sign up to request clarification or add additional context in comments.

1 Comment

cmca Over a year ago

sorry for the late reply, so im still having trouble, basically i want to use that variable in another function further down, but the way javascript runs means the 'choice' just keeps the undefined value even once the button has been pressed. Any way around this?

Parthipan Natkunam · Accepted Answer · 2016-08-31 06:49:34Z

1

Please consider assigning the "choice" variable to a global variable, so that it can be accessed outside the function. Sample snippet is as follows:

<button id="1" onclick="changeVal('val1')">b1</button>
<button id="2" onclick="changeVal('val2')">b2</button>
<button id="3" onclick="display()">Display Value</button>
<script>
    var value = "";
    var globalChoice ="";
    function changeVal(choice) {
        if (choice == 'val1') {
            value = 'number value 1';
        } else if (choice == 'val2'){
            value ='number value 2';
        }
       globalChoice = choice;
    }
    function display(){
        alert(globalChoice);
    }

</script>

answered Aug 31, 2016 at 6:49

Parthipan Natkunam

7941 gold badge11 silver badges16 bronze badges

1 Comment

cmca Over a year ago

thanks for the quick reply, will implement and see how i go

Collectives™ on Stack Overflow

Changing value of JS variable depending on HTML button selected?

2 Answers 2

1 Comment

1 Comment

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

2 Answers 2

1 Comment

1 Comment

Your Answer

Sign up or log in

Post as a guest

Related