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JavaScript

Hung Pham Viet
Hung Pham Viet
9,104 Points
Posted by Hung Pham Viet
Hung Pham Viet
9,104 Points

Javascript code doesn't work, pls help?

I am doing a javascript code to make bulb on and off. If I use document.getElementById then my code work but if I use document.getElementsByTagName then it doesn't work. I don't quite understand why. Can anyone help me out?

My code that works:

------------------------------HTML code --------------------------------------

<!DOCTYPE html> <html> <head> <meta charset="utf-8"> <title>Practicing Javascript</title> <link rel="stylesheet" href="main.css" type="text/css"> </head> <body> <img id="image" src="bulboff.jpg"/> <script type="text/javascript" src="myscript.js"></script> </body> </html>

----------------------------- CSS code -----------------------------------------

img { height: 250px; width: 200px; }

------------------------ JAVASCRIPT code -----------------------------------

var imgHolder = document.getElementById("image");

var lighton = function() { this.src = "bulbon.jpg"; }

var lightoff = function() { this.src = "bulboff.jpg"; }

imgHolder.onmousedown = lighton;

imgHolder.onmouseup = lightoff;

BUT IF I CHANGE Javascript code as var imgHolder = document.getElementsByTagName("img"), it doesn't work again???

HELP HELP pls?

Hung Pham Viet
Hung Pham Viet
9,104 Points
Hung Pham Viet
Hung Pham Viet
9,104 Points

Thanks but the default of Javascript is getElementsByTagName. Must have "s" after "Element".

2 Answers

Rick Bunch
Rick Bunch
4,000 Points
Rick Bunch
Rick Bunch
4,000 Points

Try this?

------------------------ JAVASCRIPT code -----------------------------------

var imgHolder = document.getElementById("image");

var lighton = function() { imgHolder.src = "bulbon.jpg"; }

var lightoff = function() { imgHolder.src = "bulboff.jpg"; }

imgHolder.onmousedown = lighton;

imgHolder.onmouseup = lightoff;

Hung Pham Viet
Hung Pham Viet
9,104 Points
Hung Pham Viet
Hung Pham Viet
9,104 Points

Thank you Rick. Your code works of course.

My concern is how can I use "getElementsByTagName" to make this code also works as well?

I am just learning Javascript few days so I really want to attack a problem with multiple solutions.