front-end-developer_1_

Front-End-Developer - Level 1
$(document).ready(function() {
var age = parseInt(prompt("How old are you?"));
if (age > 21) {
$('#drinks').show();
} else if (age === 21) {
alert("Now don't go crazy!");
$('#drinks').show();
} else {
$('#under-21').show();
}
});
Notice the triple equals operator. When we're asking whether something is equal, we use
=== (3 equal signs). When we're setting a variable equal to something, we use = . Mixing
these up is one of the easiest syntax errors to make.
JavaScript also has an operator with 2 equal signs, but it is almost never used, and you
should generally avoid it. It does things like return true for "2" == 2 , but many of its rules
are confusing, inconsistent, and hard to remember.
When JavaScript tries to figure out if the condition is true, it's looking for a boolean.
Remember booleans - true and false ? They were returned from the confirm() function.
Check out what's going on here in the JavaScript console:
var age = 22;
age > 21;
We're getting a boolean, just like with confirm() . We could write the JavaScript for our
drinks page like this:
scripts.js
$(document).ready(function() {
var over21 = confirm("Are you over 21? Click OK for yes or Cancel for no.");
if (over21) {
$('#drinks').show();
} else {
$('#under-21').show();
}
});
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