how to change <img src> with javascript-CodePudding

I have a Javascript function that I been dealing with for a few hours,

Javascript:

var musicFile = new Audio('audio/Ice.mp3');
var audioState = document.getElementById('musicIcon');

function music() {
    if (audioState.src = 'images/musicOff.svg') {
        musicFile.play();
        audioState.src = 'images/musicOn.svg';
    } else if(audioState.src = 'images/musicOn.svg') {
        musicFile.pause();
        musicFile.currentTime = 0;
        audioState.src = 'images/musicOff.svg';
    }
}

HTML:

<ul class="tabs" style="top: 0px; right: 0px; width: 210px; right: 10px; text-shadow: 1px 1px indigo;">
    <li class="tab" onclick="music()">
        <img id="musicIcon" src="images/musicOff.svg" width="32" height="32">
    </li>
</ul>

CSS:

.tabs {
    position: absolute;
    display: flex;
    list-style-type: none;
    margin: auto;
    padding: 0px;
    width: 800px;
    height: 30px;
}
.tab {
    position: relative;
    top: 30%;
    width: 15%;
    height: 20px;
    background:royalblue;
    border: 0px transparent;
    border-radius: 10px;
    padding: 10px;
    margin: 0px;
    margin-right: 15px;
    text-align: center;
    font-size: 16px;
    font-family: monospace;
    color: white;
    cursor: pointer;

}
.tab:hover {
    text-align:center;
    background-color: #CCC;
}

The <li> tag is meant to act as a button, and it does everything in the function, (changes .svg Icon and plays the music) but the second time I click it again, nothing happens. I also checked the console, and no errors.

I would really appreciate some help, and maybe some tips in general. (New to Javascript, not looking to use jQuery right now.)

CodePudding user response：

There's a couple of things going on with your example:

To compare values your need to either use double == (loose comparison) or triple === (strict comparison) equal signs.
It might be that you are calling var audioState = document.getElementById('musicIcon'); too early, because the document has not been fully parsed yet, and so audioState will be null, instead of the element.
audioState.src will return the full URI to the source after you have assigned a value to it. So comparing it to the relative URI will not match.

Here's a working example, putting it all together (I left out the audio file part):

var audioState;
// create absolute URIs from relative URIs of the images, resolved against document.documentURI
var imageOffUri = new URL('images/musicOff.svg', document.documentURI);
var imageOnUri = new URL('images/musicOn.svg', document.documentURI);
function music() {
    if (audioState.src == imageOffUri) {
        audioState.src = imageOnUri;
        console.log('turned on');
    } else if(audioState.src == imageOnUri) {
        audioState.src = imageOffUri;
        console.log('turned off');
    }
}

// wait for the document to be fully parsed
document.addEventListener('DOMContentLoaded', function() {
  audioState = document.getElementById('musicIcon');
});

.tabs {
    position: absolute;
    display: flex;
    list-style-type: none;
    margin: auto;
    padding: 0px;
    width: 800px;
    height: 30px;
}
.tab {
    position: relative;
    top: 30%;
    width: 15%;
    height: 20px;
    background:royalblue;
    border: 0px transparent;
    border-radius: 10px;
    padding: 10px;
    margin: 0px;
    margin-right: 15px;
    text-align: center;
    font-size: 16px;
    font-family: monospace;
    color: white;
    cursor: pointer;

}
.tab:hover {
    text-align:center;
    background-color: #CCC;
}

<!DOCTYPE html>
<html>
<head>
  <meta charset="utf-8">
  <title></title>
</head>
<body>
  <ul class="tabs" style="top: 0px; right: 0px; width: 210px; right: 10px; text-shadow: 1px 1px indigo;">
      <li class="tab" onclick="music()">
          <img id="musicIcon" src="images/musicOff.svg" width="32" height="32">
      </li>
  </ul>
</body>
</html>

CodePudding user response：

you're forgetting to use double equals to do a comparation. Change = to ==

audioState.src is returning absolute path, try change it for the method getAttribute('src') on all comparations. like that:

audioState.getAttribute('src') == 'images/musicOff.svg'

and to change src value, try to use setAttribute('attribute', 'newValue') method like that:

audioState.setAttribute('src', 'images/musicOff.svg');

hope it help u

CodePudding user response：

you are using = instead of == or === so change

audioState.src = 'images/musicOff.svg'

audioState.src == 'images/musicOff.svg'