How can I change global variables in javascript?
Question
My html page displays a button that calls a function when it is clicked. I checked to make sure that the button works properly by displaying a message when clicked and it worked. I created this function to change the global varible but when I click another button on my html page to show the value of the varibles the varibles have not changed to the value I set them using my function. Could someone find the problem in my code below?
var a = 5;
var b = 16;
var c = 27;
function reset(){
a = 0;
b = 0;
c = 0;
}
My html code to call the function:
<!DOCTYPE HTML>
<html>
<center>
<script type="text/javascript" src="game.js" > </script>
<form>
<input type="button" value="Reset Variables" style="width:250px;height:50px" onclick="reset()" >
</form>
</html>
Javascript code to show the variables:
function display(){
document.write("A is equal to " + a + "<br/>");
document.write("B is equal to " + b + "<br/>");
document.write("C is equal to " + c );
}
Html to display the variables
<!DOCTYPE HTML>
<html>
<center>
<script type="text/javascript" src="game.js" > </script>
<form>
<input type="button" value="Show Variables" style="width:250px;height:50px" onclick="display()" >
</form>
</html>
2 answers
solution1
0 2013-04-08 21:41:06
That can`t work, because you are asserting that variables in function scope. But your variables are currently stored in global scope (window), so this code will work:
var a = 5;
function reset() {
console.log(window.a); // 5
window.a = 10;
}
reset();
console.log(a); // 10
solution2
0 ACCPTED 2013-04-08 22:18:33
change the function name to reset_vars or anything else. reset() is in-built DOM function used for resetting forms.
http://www.w3schools.com/jsref/met_form_reset.asp
There won't be any conflict when a global variable is used inside a function unless a local variable is defined. in such case, use window.variable_name to access global variable.
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