JavaScript onClick addClass

Question

I am kind of confused why my code doesn't work correctly, I hope You will tell me what I've done wrong. I want to highlight navigation tab while clicked.

HTML:

<header class="mainheader">
  <!-- Obrazek tutaj-->
  <nav>
    <ul>
      <li><a id="a-home" onclick="dodajAktywne(this)" href="index.html">Home</a></li>
      <li><a id="a-omnie" onclick="dodajAktywne(this)" href="omnie.html">O mnie</a></li>
      <li><a id="a-kurs" onclick="dodajAktywne(this)" href="kurs.html">Kurs</a></li>
      <li><a id="a-kontakt" onclick="dodajAktywne(this)" href="kontakt.html">Kontakt</a></li>
    </ul>
  </nav>
</header>

JavaScript:

   function dodajAktywne(elem) {
    var a = document.getElementsByTagName('a')
    for (i = 0; i < a.length; i++) {
        a[i].classList.remove('active');
    }
    elem.classList.add('active');
}

CSS:

.active {
    color: blue;
    background-color: #cf5c3f;
}

You should pass this to pass the element itself to the function. — SLaks
– SLaks, Commented Nov 16, 2014 at 16:30
OP code is working fiddle. I think he means when he clicks the link doesn't keep the style.. — Alex Char
– Alex Char, Commented Nov 16, 2014 at 16:32
Without the actual code it is difficult to tell, I assume that you plan to include your <header> tag in every page you have exactly as you have it posted. If this is so, then you problem is that as a link is clicked the page is reloaded and your changes (add class) are discarded. For the future it is best if you would provide a repro using jsfiddle or plunker — mfeingold
– mfeingold, Commented Nov 16, 2014 at 16:33
@AlexChar which leads to a conclusion that i.e: omnie.html is being followed. — Roko C. Buljan
– Roko C. Buljan, Commented Nov 16, 2014 at 16:36
fiddle add return false; if you dont want to redirect the page — Vitorino fernandes
– Vitorino fernandes, Commented Nov 16, 2014 at 16:37

Weafs.py · Accepted Answer · 2014-11-16 16:46:23Z

24

You can simplify your JavaScript to:

Fiddle

function dodajAktywne(elem) {
    // get all 'a' elements
    var a = document.getElementsByTagName('a');
    // loop through all 'a' elements
    for (i = 0; i < a.length; i++) {
        // Remove the class 'active' if it exists
        a[i].classList.remove('active')
    }
    // add 'active' classs to the element that was clicked
    elem.classList.add('active');
}

If you pass the parameter this in your HTML to:

<header class="mainheader">
    <!-- Obrazek tutaj-->
    <nav>
        <ul>
            <li><a id="a-home" onclick="dodajAktywne(this)" href="#">Home</a>
            </li>
            <li><a id="a-omnie" onclick="dodajAktywne(this)" href="#">O mnie</a>
            </li>
            <li><a id="a-kurs" onclick="dodajAktywne(this)" href="#">Kurs</a>
            </li>
            <li><a id="a-kontakt" onclick="dodajAktywne(this)" href="#">Kontakt</a>
            </li>
        </ul>
    </nav>
</header>

Note: I've changed href attribute to #, you will have to change it back to your .html pages

Alternatively, you can do this without JavaScript, using CSS's :focus:

Fiddle

a:focus {
    color: blue;
    background-color: #cf5c3f;
}

edited Nov 16, 2014 at 16:46

answered Nov 16, 2014 at 16:37

Weafs.py

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6 Comments

Sheil Over a year ago

I have tried both options, none of them are working as intended. Nav buttons just lose their focus.

Weafs.py Over a year ago

@user3703750 - You want the previous button to be active, even if another button is clicked?

Sheil Over a year ago

None is active. When I click on another link i.e. home, I want Home button from navigation to be active and highlighted.

Sheil Over a year ago

The problem is that my page is redirecting when I click on any tab from navigation. When I've stopped redirecting Your code works perfectly.

Sheil Over a year ago

jsfiddle.net/pb95kv32/2 This is how I made this. Works correctly now. Thx for help, I'll vote You up :)

|

Michael McGinnis · Accepted Answer · 2017-10-08 06:40:05Z

3

This code will highlight the navigation tab without needing to include onclick in the HTML, though it doesn't remove the background color if another tab is clicked.

    document.onclick = function(event) {
         var target = event.target || event.srcElement;
         target.style.background = '#cf5c3f';
        };

https://codepen.io/mdmcginn/pen/BwrNaj/

answered Oct 8, 2017 at 6:40

Michael McGinnis

1,02910 silver badges27 bronze badges

Comments

Đức Lê · Accepted Answer · 2019-01-16 08:06:14Z

0

var list = document.querySelector('ul');
list.addEventListener('click', function(ev) {
  if (ev.target.tagName === 'LI') {
    ev.target.classList.toggle('checked');
  }
}, false);

answered Jan 16, 2019 at 8:06

Đức Lê

11

1 Comment

Dmitry Over a year ago

Please add explanation to your answer.

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