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JavaScript

Posted by Dhawal Chheda
Dhawal Chheda
4,597 Points

Can someone give an instance when the var keyword becomes problematic to use ?

As Andrew said in the video that sometimes using var keyword becomes problematic in javascript. However, I can't think of instance when it has become problematic. So can you please share the instance when you faced problem when declaring the variable with "var" keyword.

1 Answer

Steven Parker
Steven Parker
243,656 Points
Steven Parker
Steven Parker
243,656 Points

Here's a good example.

This HTML and JavaScript code will display three buttons. Clicking any button will open an alert identifying the button by number.

But try replacing the let with var and you will find that all buttons report the button quantity instead of their individual number.

test.html 
<button>Button 0</button> <button>Button 1</button> <button>Button 2</button>
test.js 
var buttons = document.getElementsByTagName("button");

for (let i = 0; i < buttons.length; i++) {   // <- replace let with var on this line
  buttons[i].onclick = () => alert("Button " + i);
}