Cannot target button element on mousemove event

My js code is supposed to target the button class and add the cursor-hover-nav on my cursor class

I tried adding a padding on my button and the script worked only when I hovered over the padding and not its main element. Any reasons why it wont work over the main element?

window.addEventListener("mousemove", function(e) {

  if (e.target.className === 'nav-button') {
    cursor.classList.add('cursor-hover-nav');
  } else {
    cursor.classList.remove('cursor-hover-nav');
  }
});

<button onclick="show()" class="nav-button">
  <svg class="plus" viewbox="0 0 100 100" width="40">
    <rect class="line vert" 
      width="80" height="10" x="10" y="45" rx="6">
    </rect>
    <rect class="line horiz" 
     width="10" height="80" x="45" y="10" rx="6">
    </rect>
  </svg>
</button>

Solution

The problem is caused by SVG element, it's not clear why, we need a SVG expert here, but since you need it only for graphics, just add pointer-events: none to it. Also I would suggest to check the hover with if (e.target.closest('.nav-button')) since it's more stable when you add child elements to the button.

But mousemove isn't a good for hover effects since it triggered not precisely. Use mousenter and mouseleave.

window.addEventListener("mousemove", function(e) {
  Object.assign(cursor.style, {left: e.clientX + 'px', top: e.clientY + 'px'});
  if (e.target.closest('.nav-button')) {
    cursor.classList.add('cursor-hover-nav');
  } else {
    cursor.classList.remove('cursor-hover-nav');
  }
});

.as-console-wrapper{
  max-height: calc(100% - 80px) !important;
}
.nav-button svg{
  pointer-events: none;
}
#cursor{
  width: 8px;
  height: 8px;
  position: absolute;
  margin-top: 16px;
  margin-left: 16px;
  background: yellow;
}
#cursor.cursor-hover-nav{
  background: red;
}

<button onclick="show()" class="nav-button">
  <svg class="plus" viewbox="0 0 100 100" width="40">
    <rect class="line vert" 
      width="80" height="10" x="10" y="45" rx="6">
    </rect>
    <rect class="line horiz" 
     width="10" height="80" x="45" y="10" rx="6">
    </rect>
  </svg>
  <span>TEXT</span>
</button>
<div id="cursor"></div>