Why can't I assign a variable inside a function in Javascript?

Question

Very new to JS here. When I write PHP I have no problem assigning variables inside a function, but inside a JavaScript function it doesn't work. Why?

example:

function hello() {

var animal = 'Dog';
document.write(animal);

}

Answer 1

Are you calling the hello() function anywhere? If not, you will not execute the contents of the function and thus, no write will happen.

Answer 2

put this snippet inside your function to check if your function is being called

alert('snippet');

If a message box appears, your code should work, but if it does not then the function is not being executed, post some html coding also.