JavaScript DHTML/jQuery/Selector first last
Содержание
- 1 firstChild(): One for each parent.
- 2 first() matches only a single element
- 3 Get first child ID
- 4 Get first paragraph
- 5 Get last paragraph
- 6 lastChild() : One for each parent.
- 7 last() matches the last selected element.
- 8 Matches the first selected element
- 9 Matches the last selected element
- 10 Select first span
firstChild(): One for each parent.
<source lang="html4strict">
<html>
<head>
<script type="text/javascript" src="js/jquery-1.3.2.js"></script>
<script type="text/javascript">
$(document).ready(function(){
$("div span:first-child")
.css("text-decoration", "underline")
.hover(function () {
$(this).addClass("red");
}, function () {
$(this).removeClass("red");
});
});
</script>
<style>
span { color:#008; }
span.red { color:red; font-weight: bolder; }
</style>
</head>
<body>
<body>
A, B, C
D, E, F
</body>
</html>
</source>
first() matches only a single element
<source lang="html4strict">
<html>
<head>
<script type="text/javascript" src="js/jquery-1.3.2.js"></script>
<script type="text/javascript">
$(document).ready(function(){
$("tr:first").css("background-color", "red");
});
</script>
</head>
<body>
<body>
| TD #0 | TD #1 | TD #2 |
| TD #3 | TD #4 | TD #5 |
| TD #6 | TD #7 | TD #8 |
</body>
</html>
</source>
Get first child ID
<source lang="html4strict">
<html>
<head>
<script type="text/javascript" src="js/jquery-1.3.2.js"></script>
<script type="text/javascript">
$(document).ready(function(){
$("#container").click(function (e) {
var $ch = $(e.target).children();
$("#results span:first").text($ch.length);
e.preventDefault();
return false;
});
});
</script>
</head>
<body>
<body>
This is the way we write the demo,
Found 0 children in TAG.
</body>
</html>
</source>
Get first paragraph
<source lang="html4strict">
<html>
<head>
<script type="text/javascript" src="js/jquery-1.3.2.js"></script>
<script type="text/javascript">
$(document).ready(function(){
var str = $("p:first").text()+"added";
$("p:last").html(str);
}); </script> </head> <body> <body>
asdf
asdf
asdf
asdf
</body>
</html>
</source>
Get last paragraph
<source lang="html4strict">
<html>
<head>
<script type="text/javascript" src="js/jquery-1.3.2.js"></script>
<script type="text/javascript">
$(document).ready(function(){
var str = $("p:first").text()+"added";
$("p:last").html(str);
}); </script> </head> <body> <body>
asdf
asdf
asdf
asdf
</body>
</html>
</source>
lastChild() : One for each parent.
<source lang="html4strict">
<html>
<head>
<script type="text/javascript" src="js/jquery-1.3.2.js"></script>
<script type="text/javascript">
$(document).ready(function(){
$("div span:last-child")
.css("text-decoration", "underline")
.hover(function () {
$(this).addClass("red");
}, function () {
$(this).removeClass("red");
});
});
</script>
<style>
span { color:#008; }
span.red { color:red; font-weight: bolder; }
</style>
</head>
<body>
<body>
A, B, C
D, E, F
</body>
</html>
</source>
last() matches the last selected element.
<source lang="html4strict">
<html>
<head>
<script type="text/javascript" src="js/jquery-1.3.2.js"></script>
<script type="text/javascript">
$(document).ready(function(){
$("tr:last").css({backgroundColor: "yellow", fontWeight: "bolder"});
});
</script>
</head>
<body>
<body>
| First |
| Middle |
| Last |
</body>
</html>
</source>
Matches the first selected element
<source lang="html4strict">
<html>
<head>
<script type="text/javascript" src="js/jquery-1.3.2.js"></script>
<script type="text/javascript">
$(document).ready(function(){
$("tr:first").css("font-style", "italic");
});
</script>
</head>
<body>
| Row 1 |
| Row 2 |
| Row 3 |
</body>
</html>
</source>
Matches the last selected element
<source lang="html4strict">
<html>
<head>
<script type="text/javascript" src="js/jquery-1.3.2.js"></script>
<script type="text/javascript">
$(document).ready(function(){
$("tr:last").css("font-style", "italic");
});
</script>
</head>
<body>
| Row 1 |
| Row 2 |
| Row 3 |
</body>
</html>
</source>
Select first span
<source lang="html4strict">
<html>
<head>
<style>
.test{ border: 1px solid red; }
</style>
<script type="text/javascript" src="js/jquery-1.3.2.js"></script>
<script type="text/javascript">
$(document).ready(function(){
$("span:first").text($(":hidden", document.body).length + " hidden elements.");
});
</script>
</head>
<body>
<form>
<input type="hidden" />
<input type="hidden" />
<input type="hidden" />
</form>
</body>
</html>
</source>
