Strange javascript bug

Question

Pls look at the following code: html...

 <pre id='output'></pre>

html...

JS

 function log(text) {
    var div = document.getElementById('output');
    div.innerHTML += text + '\n';
 }

function foo() {

    var browser=0;
    if(navigator.appName.toUpperCase()=="MICROSOFT INTERNET EXPLORER")
        browser=1;
    else
    if(navigator.appName.toUpperCase()=="NETSCAPE")
        browser=2;
    log ('browser:'+browser);
    if (browser==1)
    {
        log ('IE');
    }
    if (browser==2);
    {
        log ('Chrome');
    }

    if (browser==0);
    {
            log ('Could not determine broweser type');
            return;
    }
  }

When I run this from IE the output is: browser:1 ie not supported Chrome extension will be loaded Could not determine broweser type

When I run it from Chrome the output is: browser:2 Chrome extension will be loaded Could not determine broweser type

How can it be that browser has more than one value? 10xs, Nir

That code could not possibly produce that output, so what is the actual code and the actual output? — Guffa
– Guffa, Commented Oct 21, 2012 at 15:00

Clyde Lobo · Accepted Answer · 2012-10-21 14:59:46Z

3

You have a very beginners mistake in your code

The ; at the end of the if if (browser==0); causes your if condition to end and the rest is a normal code block which gets executed every time no matter the value of browser

answered Oct 21, 2012 at 14:59

Clyde Lobo

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2 Comments

Shuping Over a year ago

Clyde Lobo shows the correct answer. when you encounter JS issues, it's better to debug it with Developer Tool (F12) from your browsers. by setting a break point, it could be easy to find this code bug.

Bergi Over a year ago

the same after if (browser == 2);

pckill · Accepted Answer · 2012-10-21 15:00:16Z

0

You should not put ; after an if statement: if (browser==2);

answered Oct 21, 2012 at 15:00

pckill

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