Else if and Else in JavaScript

Question

I wrote a small javascript code, but it has a problem, the page can not show anything. I think the problem is in the line "else if..." or "else...", because if I comment these two lines, the code runs without any problem

<html>
<head>
    <script language="javascript">
        var var1 = window.prompt("please input");
        var var2 = window.prompt("please input2");
        var1 = parseFloat(var1);
        var2 = parseFloat(var2);

        if (var1< var2) {document.writeln("the second number is bigger")};
        else if (var1> var2) {document.writeln("the first number is bigger")};
        else {document.writeln("They are the same")};
    </script>
</head>
<body>
</body>
</html>

Remove the ; from the closing braces of your if statements. — www139
– www139, Commented Dec 25, 2015 at 18:58
Welcome to Stackoverflow. Merry Christmas and hope you are successful at learning JavaScript. — www139
– www139, Commented Dec 25, 2015 at 18:59

rishabh dev · Accepted Answer · 2015-12-25 19:00:15Z

3

Your javascript should be like this

var var1 = window.prompt("please input");
var var2 = window.prompt("please input2");
var1 = parseFloat(var1);
var2 = parseFloat(var2);

if (var1 < var2) {
  document.writeln("the second number is bigger");
} else if (var1 > var2) {
  document.writeln("the first number is bigger");
} else {
  document.writeln("They are the same");
}

answered Dec 25, 2015 at 19:00

rishabh dev

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2 Comments

Phiter Over a year ago

I beat you to an answer earlier today, also, Praveen ;D

Praveen Kumar Purushothaman Over a year ago

@PhiterFernandes Merry Christmas! LoL.

Community · Accepted Answer · 2017-05-23 12:31:22Z

1

Try removing the semicolon, ;, from after the brackets of your if statements:

    if (var1< var2) {document.writeln("the second number is bigger")}
    else if (var1> var2) {document.writeln("the first number is bigger")}
    else {document.writeln("They are the same")}

Have a look at this SO answer: https://stackoverflow.com/a/17036218/4206206

Essestially, a semicolon isn't used to end a group of statements, but rather to end a single statement.

A point with your code, if you're using HTML5 you don't need the language="javascript" in your script tags:

<script language="javascript">

Can become simply

<script>

edited May 23, 2017 at 12:31

CommunityBot

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answered Dec 25, 2015 at 19:02

joe_young

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Comments

J0B · Accepted Answer · 2016-01-10 14:31:39Z

1

Should be:

<html>
<head>
    <script language="javascript">
        var var1 = window.prompt("please input");
        var var2 = window.prompt("please input2");
        var1 = parseFloat(var1);
        var2 = parseFloat(var2);

        if (var1 < var2) {
            document.writeln("the second number is bigger");
        }
        else if (var1 > var2) {
            document.writeln("the first number is bigger");
        }
        else {
            document.writeln("They are the same");
        }
    </script>
</head>
<body>
</body>
</html>

your semi colons were wrong

edited Jan 10, 2016 at 14:31

answered Dec 25, 2015 at 18:59

J0B

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Comments

Nick Zuber · Accepted Answer · 2015-12-25 19:01:05Z

0

if (var1< var2) {document.writeln(" ... ")};
                                           ^

Your semicolons at the end of your if, else if, and else blocks are your issue. They are prematurely ending your if blocks.

answered Dec 25, 2015 at 19:01

Nick Zuber

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Comments

Praveen Kumar Purushothaman · Accepted Answer · 2015-12-25 19:01:16Z

-1

Just make sure you parseFloat before you compare, because it just compares as string, and remember, 10 comes before 2, so by string 10 < 2! And you don't need the ; at the end:

var var1 = window.prompt("please input");
var var2 = window.prompt("please input2");
var1 = parseFloat(var1);
var2 = parseFloat(var2);

if (var1 < var2) {
  document.writeln("the second number is bigger");
} else if (var1 > var2) {
  document.writeln("the first number is bigger");
} else {
  document.writeln("They are the same");
}

answered Dec 25, 2015 at 19:01

Praveen Kumar Purushothaman

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