Значение $(this)
равно undefined
внутри анонимной функции resize
.Если вы замените $(this)
на $('nav')
, все будет работать, как и ожидалось.
Короче, замените это…
$(window).resize(function() {
…
var firstChild = $(this).find("a:first-child");
}
… этим
$(window).resize(function() {
…
var firstChild = $("nav").find("a:first-child");
}
Демо
$(".underline-nav").css("width", $("#one").width());
$(".underline-nav").css("margin-left", $("#one").css("margin-left"));
var unav = $(".underline-nav");
$("nav a").mouseover(function() {
$(".underline-nav").css("transition", "all ease 0.43s");
var position = $(this).position();
unav.css({
width: $(this).width(),
"margin-left": $(this).css("margin-left"),
left: position.left
});
});
$("nav").mouseleave(function() {
$(".underline-nav").css("transition", "all ease 0.7s");
var firstChild = $(this).find("a:first-child");
var position = firstChild.position();
unav.css({
width: firstChild.width(),
"margin-left": firstChild.css("margin-left"),
left: position.left
});
});
//NEW BUT CAUSES ERROR
var resizeTimer;
$(window).resize(function() {
clearTimeout(resizeTimer);
$(".underline-nav").css("transition", "all ease 0.7s");
var firstChild = $("nav").find("a:first-child");
var position = firstChild.position();
console.log("position", position);
unav.css({
width: firstChild.width(),
"margin-left": firstChild.css("margin-left"),
left: position.left
});
});
html {
background-color: blue;
}
body {
margin: 0;
}
.underline-nav {
background: tomato;
height: .25rem;
position: absolute;
top: 6vh;
margin-top: 1vw;
transform: translatex(4vw);
transition: all ease 0.37s;
z-index: 0;
}
.mainnav {
padding-top: 1vh;
width: 100%;
position: absolute;
z-index: 4;
font-size: 0.8vw;
text-align: center;
display: flex;
justify-content: center;
align-items: center;
}
nav img {
padding-left: 4vw;
height: 3.5vw;
}
a {
color: #fff;
text-decoration: none;
font-weight: 700;
padding-left: 4vw;
letter-spacing: 0.4em;
}
.sectionone {
height: 100vh;
background: url('media/bg.jpg') no-repeat center center fixed;
background-size: cover;
color: #fff;
font-family: 'Raleway';
}
<script src="https://cdnjs.cloudflare.com/ajax/libs/jquery/3.3.1/jquery.min.js"></script>
<nav>
<div class="mainnav">
<a id="one" href="#">HOME</a>
<a href="#">LINK 1</a>
<a href="#">LINK 2</a>
<img src="/media/Asset 1.png" alt="logo">
<a href="#">LINK 3</a>
<a href="#">LINK 4</a>
<a href="#">LINK 5</a>
<div class="underline-nav">
</div>
</div>
</nav>