javascript element.className error?

Question

I am trying to get the body's classname to use in an if/else statement in plain javascript.

To my surprise the element.className trows me errors everytime:

Uncaught TypeError: Cannot read property 'className' of undefined

 alert( document.getElementsByTagName("body")[0].className.match("home") );
 alert( document.getElementById("container").className.match("fooclass") );

<body class="home page">
 <div id="container" class="fooclass"></div>
</body>

can you try after putting your code in document.onload event? — gurvinder372, Mar 10 '16 at 09:02
Because here you script tags are appended after the elements — gurvinder372, Mar 10 '16 at 09:04
As @gurvinder372 suggests, this probably gets caused by the DOM not having rendered yet. — Matthijs, Mar 10 '16 at 09:04
Can't you use `document.body`? Or is it better practice to use `document.getElementsByTagName("body")` instead? — ste2425, Mar 10 '16 at 09:05

score 0 · Answer 1 · answered Mar 10 '16 at 09:05

0

Try this

window.onload = function(){

    alert( document.getElementsByTagName("body")[0].className.match("home") );
    alert( document.getElementById("container").className.match("fooclass") );

}

You can put this anywhere on the page ;)

answered Mar 10 '16 at 09:05

gurvinder372

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javascript element.className error?

1 Answers1