:first-of-type选择器用于选择所有作为其父级的第一个子级(特定类型)的元素。
语法如下：
$(":first-of-type")以下示例说明了jQuery中的：first-of-type选择器：
范例1：本示例将其父母的第一个标题(div标签)的背景颜色更改为绿色, 将文本颜色更改为白色。
<!DOCTYPE html>
<html>
<head>
<title>
jQuery | :first-of-type Selector
</title>
<script src =
"https://ajax.googleapis.com/ajax/libs/jquery/3.3.1/jquery.min.js">
</script>
<!-- Script to use first-of-child selector -->
<script>
$(document).ready(function() {
$("h4:first-of-type").css({
"background-color": "green", "color": "white"
});
});
</script>
<style>
option {
font-weight: bold;
font-size: 25px;
color: green;
}
select {
font-weight: bold;
font-size: 25px;
color: green;
}
</style>
</head>
<body style = "text-align:center; width: 500px; margin: auto">
<h1>
jQuery | :first-of-type Selector
</h1>
<div style = "border:1px solid blue;">
<h4>The first heading in first div.</h4>
<h4>The last heading in first div.</h4>
</div><br>
<div style = "border:1px solid blue;">
<h4>The first heading in second div.</h4>
<h4>The last heading in second div.</h4>
</div>
</body>
</html>输出如下：
范例2：本示例将<body>标签的第一个标题的背景颜色更改为绿色, 将文本颜色更改为白色。
<!DOCTYPE html>
<html>
<head>
<title>
jQuery | :first-of-type Selector
</title>
<script src =
"https://ajax.googleapis.com/ajax/libs/jquery/3.3.1/jquery.min.js">
</script>
<!-- Script to use first-of-child selector -->
<script>
$(document).ready(function() {
$("h4:first-of-type").css({
"background-color": "green", "color": "white"
});
});
</script>
<style>
option {
font-weight: bold;
font-size: 25px;
color: green;
}
select {
font-weight: bold;
font-size: 25px;
color: green;
}
</style>
</head>
<body style = "text-align:center; width: 500px; margin: auto">
<h1>
jQuery | :first-of-type Selector
</h1>
<h4>The first heading in body.</h4>
<h4>The last heading in body.</h4>
</body>
</html>输出如下：
