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I have the following code in HTML which creates a button, that when clicked creates some questions in my page, works fine. 

<input type="number" name="quantity" id="num_questions" min="1" max="99"><br>
<input type="button" name="go" id="go_button" value="Go" onclick="createQuestions()"><br>

However, within my function createQuestions() I have defined a variable in JavaScript, which is based on a number input from my HTML code, shown above.

var number = document.getElementById('num_questions').value;

I have another button which calls a separate function but I need that variable number I locally defined in another function. Is there any way I can grab that variable and use it globally? I tried defining it outside my function, but since the onclick event only calls that one function, it won't create the variable.

Other button:

<input type="submit" name="submit" value="Create Tree" onclick="displayData()">
j08691
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Tim
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  • You should be able to access the `number` variable anywhere if you define it globally. The when you run your `createQuestions()` function you can assign it to a value. Can you post the rest of your JS here? It would be helpful to fully solve the problem. – Coleman Jun 23 '16 at 20:00
  • Possible duplicate of [Define global variable in a JavaScript function](http://stackoverflow.com/questions/5786851/define-global-variable-in-a-javascript-function) – But those new buttons though.. Jun 24 '16 at 00:25

2 Answers2

2

According to How to declare a global variable in a .js file you can define a variable before any function is called and then use it in different functions.

var global1 = "I'm a global!";

function setGlobal () {
    global1= document.getElementById('num_questions').value;
}
function testGlobal () {
    alert(global1);
}
Community
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keiv.fly
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  • But when I call that function setGlobal() on a button click, the variable will not be declared, since the button click is calling ONLY the function.. – Tim Jun 23 '16 at 20:04
  • You may not declare it inside the function, but you can reassign the variable. And it will be accessible, because it is global. – keiv.fly Jun 23 '16 at 20:06
  • Aha! There we go, this is exactly what I needed. I wonder why I never thought of this. Thanks! – Tim Jun 23 '16 at 20:10
1

It is not possible to access a function's local variables from outside of that function, so you have four options:

  1. Declare a global variable!
  2. Write a separate function that grabs the value for you
  3. Create an object that contains the value you need
  4. Grab the value from within your new function using getElementById()
Vincent Rodomista
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