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Hide DIV element with onclick command

Thanks to anyone who helps me solve this issue.
So the issue is I'm trying to hide an element (by class) with an onclick event using a button. But I am unable to do so.
Here's the code on jsfiddle http://jsfiddle.net/1tpdgrnj/
Here's the code for those who wish to help me here:
HTML:
<div class="box">Hide on button click!!
<button onclick="close();">Close</button>
Javascript:
function close() {
document.getElementsByClassName("box").style.display = 'none';}
UPDATE
Refer to the answer below and to the jsfiddle to see how it's different.

See this fiddle
Change your javascript as follows
function myFunction() {
document.getElementsByClassName("box")[0].style.display = 'none';
}
First change that should be done is, rename your function name, as close is a keyword in Javascript.
Second one is that, document.getElementsByClassName() returns an array and thus to get the first element you should use the index position 0.
According to the docs
The Element.getElementsByClassName() method returns a live
HTMLCollection containing all child elements which have all of the
given class names. When called on the document object, the complete
document is searched, including the root node.
Read more about it here

You can use Jquery
<div class="box">Hide on button click!!
<button class="close">Close</button>
</div>
<script src="https://ajax.googleapis.com/ajax/libs/jquery/1.11.3/jquery.min.js"></script>
<script>
$(document).ready(function(){
$(".close").click(function(){
$(this).parent().hide(); return false;
});
});
</script>

Check this fiddle
You can also do this easily with jQuery.
$("#hide").click(function(){
$(".box").fadeOut(150);
});

Im forcing to use getElementsByClassName()[] rather than getElementByClass()

I have 8 divs with id="div1","div2","div3".... and a class=divs. I also have a button with class="div1","div2","div3"......
When I click the button with id="div1", it will first remove all the class="selected" to all div that has a class="divs" then only the div with id="div1" will have the class selected. And so on.....
I want to use document.getElementByClass() for removing class but it don't work in my FIDDLE. :(
Instead, Im forced to use document.getElementsByClassName()[]. But it seems so hard to code since it requires me to put the specific arrays for the classname.
This is exactly I want to achieve FIDDLE

There is no getElementByClass for a reason: unlike id, class is not specified to be unique in a document. Which element would you get? No, you need the ability to get all of them. And if you get an array, that's solved by looping, not by repeating rows for each index:
However, your design is inefficient; and if you're already using jQuery, you can write it very tightly. This would be better:
<button class="divbuttons" data-div="div1">div1</button>
<button class="divbuttons" data-div="div2">div2</button>
...
then you can:
$(document).ready(function(){
$('.divbuttons').click(function() {
var div = $(this).data("div");
$('.divs.selected').removeClass('selected');
$('#' + div).addClass('selected');
});
});

This is an easy one. There is no document.getElementByClass
You have document.getElementById or document.getElementByClassName

There's no such thing as getElementByClass() because multiple elements can have the same class. There's getElementById() (elements have unique ids, or at least they're supposed to) and getElementsByClassName(), which returns an array of all elements that match the class specified.

try
$(document).ready(function () {
$("button[class^=div]").click(function () {
$(".divs.selected").removeClass("selected");
$("#" + $(this).attr("class")).addClass("selected");
});
});
DEMO

Not able to retrieve button text JS/Jquery

I want to retrieve the text of a button that is clicked. I've read up on other suggestions for similar questions, but cant seem to get it to work. Here is the fiddle: http://jsfiddle.net/z3PKm/63/
Which currently isn't working. What am I doing wrong, or what should I do which is right?
Thanks!
I've tried to copy the following solution
alert($(this).attr("value"));
But it still doesn't work for me.

Use this:-
.text() will give you the text of the button as per your example. You are using button and not input type="button" If it was input type="button" then .val() would work.
function test(name) {
alert($(name).text());
}
Since you are using jquery you can use the click event
$('button').on('click',function(){
alert($(this).text());
});

The type of button that you are using are not using value, they are text.
Write this:
$(name).text()

This is how I would do it jQuery style.
This also show you how to use inputs and buttons and text() or val() as appropriate
$('.choose').on('click', function(){
var $this = $(this);
alert('text: '+$this.text()+'\nval: '+$this.val());
}); // end on click

You need to use alert($(name).text()); I have updated the jsfiddle with the same:
jsfiddle

jquery- store id of clicked link in variable

This should be basic, but for some reason its not working for me. I just want to store the id when a link that has a certain class is clicked in a variable so as an example:
Some link
I would want jquery to get the id of the link above and store it in a variable. I have tried $this.attr("id") and $this.id, but non of this worked.
This is what I have for the jquery:
$(".only_this_class").click(function() {
var clickedId= $(this).attr("id");
alert(clickedId);
});
I just get "undefined" every time.

I removed the space between this and _class in class="only_this _class" and it is working for me.
Try this here
Please have a look at jQuery Selectors
If you have two classes in your HTML then the syntax is different:
$('.classA.classB')
Have a look at How can I select an element with multiple classes?

NAVEED is right, if you remove the space it works, because if there is a space HTML will put two classes on the element: only_this and _class.
If you are in fact looking for two different classes, you should replace the space with a dot to make it work properly, as in $(".only_this._class")

$(".only_this _class") this selector will look for _class tag in .only_this element. May you are looking for $(".only_this") which will select element which has this class. Try this.
$(".only_this").click(function() {
var clickedId= $(this).attr("id");
alert(clickedId);
});

jQuery Function Problem (Parent/Child)

I have a small problem with a jQuery script I wrote.
I have an HTML structure like this:
<div id="navigation">
<ul>
<li><b>Text1</b></li>
<li><b>Text2</b></li>
...
</ul>
</div>
Then, I have a click function binded to those li/a tabs that sets the value of the current page to href:
var currentpage = $(this).attr('href');
And, finally, an update function that is fired when it's needed that do many thing, but also changes the style of the currently selected li/a tab:
$('#navigation a').each(function()
{
var tab = $(this);
tab.parent().toggleClass('current', (tab.attr('href') == currentpage));
});
Everything works fine, but today I was trying to rewrite the last function on one line only -without calling each()- and I can't get it to work.
I've tried many solutions like:
$('#navigation a').parent().toggleClass('current', ($(this).children(':first').attr('href') === currentpage));
$('#navigation a').parent().toggleClass('current', ($(':only-child', $(this)).attr('href') == currentpage));
Can someone help me out?
Thanks!

You can't rewrite it as you'd like to.
The original code has to use ".each()" because it needs access to each individual <a> element in order to do its thing. In your rewrite, you're imagining that you can get this set to each element being processed, but that's just not how this works in JavaScript. In your attempted rewrite, the value of this in those parameters to "toggleClass()" will be this as it stands outside that entire jQuery function call chain. It'll have absolutely nothing to do with the <a> elements being processed by the call to "toggleClass()".

when your function is triggers i.e. on clicking the in that function you can get the reference to the clicked element, tag by using $(this). Then your code should be
$(this).parent().toggleClass('current', ($(this).children(':first').attr('href') === currentpage));