CODEWITHSUNDEEP
javascript
user3490706
user3490706

Reputation: 1

Very simple JavaScript code doesn't work?

I'm a beginner on JavaScript so can someone tell me why this doesn't work?

<!doctype html>
<head>
<title>Assignment</title>
</head>

<script>
var name = ("John" & "Penny" & "Pat")
name = prompt("What is the student name?");
if (name="John" && "Penny" && "Pat")
{
document.write(name + " has one free hour of lessons.");
}
else
{
document.write(name + "doesn't have any free lessons.");
}
</script>

It will prompt me with the question but despite what I input it will always output with "Pat has one free hour of lessons." Anyone help me?

Upvotes: -2

Views: 111

Answers (3)

aneelkkhatri
aneelkkhatri

Reputation: 404

Here's what you want:

<!DOCTYPE html>
<head>
    <title>Assignment</title>
</head>
<body>
    <script type="text/javascript">
        var names = ["John","Penny","Pat"];

        var name = prompt("What is the student name?");

        if(names.indexOf(name) > -1) 
        {
            console.log(name + " has one free hour of lessons.");
        }
        else 
        {
            console.log(name + " doesn't have any free lessons.");
        }
    </script>
</body>
</html>


P.S. You should avoid using document.write. I have edited the code and changed that part to console.log

Upvotes: 0

SomeKittens
SomeKittens

Reputation: 39522

You're using the wrong equals here:

if (name="John" && "Penny" && "Pat")

Change it to 

if (name === "John" || name === "Penny" || name === "Pat")

You're also setting name incorrectly: 

var name = ("John" & "Penny" & "Pat")

should be

var name = ["John", "Penny", "Pat"];

(if you want an array.) (Though you're overwriting it in the next line, so why ever set it like that in the first place?).

Finally, it's bad practice to use document.write, try console.log instead.

To sum up so far:

var name = prompt("What is the student name?");
if (name === "John" || name === "Penny" || name === "Pat") {
    console.log(name + " has one free hour of lessons.");
} else {
    console.log(name + " doesn't have any free lessons.");
}

As noted in the comments, this gets difficult when you add more users. Instead, let's store the users who have a free hour in an array (thus, adding new students is easy, just add them to the array):

var haveFreeHour = ["John", "Penny", "Pat"];

Then, we can use indexOf in the if statement:

var haveFreeHour = ["John", "Penny", "Pat"];
var name = prompt("What is the student name?");
if (haveFreeHour.indexOf(name) > -1) {
    console.log(name + " has one free hour of lessons.");
} else {
    console.log(name + " doesn't have any free lessons.");
}

Play with this at JSFiddle

Upvotes: 4

Gabriel
Gabriel

Reputation: 327

You need to use == or === for comparison.

Here is more info on what each one does http://www.2ality.com/2011/06/javascript-equality.html

Strict equals === [ES5 11.9.6] Comparing two values. Values with different types are never equal. If both values have the same type then the following assertions hold.

Equals == [ES5 11.9.3] Comparing two values. If both values have the same type: compare with ===. Otherwise: undefined == null One number, one string: convert the string to a number A boolean and a non-boolean: convert the boolean to a number and then perform the comparison. Comparing a string or a number to an object: try to convert the object to a primitive and then make the comparison.

Also your names variable should be used as an Array and a different one for your prompt, something like :

var names = ["John", "Penny", "Pat"];
var name = prompt("What is the student name?");

Then instead of comparison you could use indexOf (more on indexOf) to see if your value is in your array, something like :

if(names.indexOf(name) > -1)...

Upvotes: 0

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