web开发中经常会碰到表单操作。表单元素的类型有text、password、select、checkbox、radio、textarea、file、hidden、button、image、reset和submit，不包括html5新类型。下面介绍这些常用的表单元素的赋值和取值操作，file类型有时间会另外写篇文章具体介绍。
text、password、textarea、hidden操作：
$("selector").val() //get value
$("selector").val(value) //set value
select 操作：
$("selector").val() //get select value
$("selector option:selected").text() //get select text
$("selector").val(value) //set value
radio 操作：
$("selector :checked").val() //get radio checked value
$("selector [value="+ value+"]").prop('checked', true); //set radio checked by value
$("selector ").eq(index).prop('checked', true); //set radio checked by index
checkbox 操作：
$("selector :checked").val() //get single checkbox checked value
//get checked array from checkbox group
var checkboxList=[];
$("selector :checked").each(function(index,item){
checkboxList.push($(this).val());
})
$("selector [value="+ value+"]").prop('checked', true); //set checkbox checked by value
$("selector ").eq(index).prop('checked', true); //set checkbox checked by index
//set checkbox checked from checked array
$("selector ").each(function(index,item){
$(this).prop("checked",$.inArray($(this).val(),checkboxList)!==-1)
})
//set all checkbox checked and not checked
$("#checkAll").click(function(){
$('input:checkbox').not(this).prop('checked', this.checked);
});
//if the checkbox is checked
$("selector ").is(':checked')
// form serialize
$('form').serialize()
综合示例:
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<title>Sign up</title>
<link href="http://cdn.bootcss.com/bootstrap/3.3.6/css/bootstrap.min.css" rel="stylesheet">
</head>
<style type="text/css">
form {
width: 600px;
margin: 50px auto;
}
</style>
<body>
<form class="form-horizontal" role="form">
<div class="form-group">
<label for="firstname" class="col-sm-2 control-label">Username:</label>
<div class="col-sm-10">
<input type="text" class="form-control" name="username" id="username" placeholder="Your username" value="">
</div>
</div>
<div class="form-group">
<label for="pwd" class="col-sm-2 control-label">Password:</label>
<div class="col-sm-10">
<input type="password" class="form-control" name="password" id="pwd" value="">
</div>
</div>
<div class="form-group">
<label for="firstname" class="col-sm-2 control-label">Education:</label>
<div class="col-sm-10">
<select class="form-control" name="education">
<option value=1>--Please select--</option>
<option value=1>Primary school</option>
<option value=2>Middle school</option>
<option value=3>Senior high school</option>
<option value=4>University</option>
</select>
</div>
</div>
<div class="form-group">
<label for="lastname" class="col-sm-2 control-label">Sex:</label>
<div class="col-sm-10">
<label class="checkbox-inline">
<input type="radio" name="sex" value=1> Male
</label>
<label class="checkbox-inline">
<input type="radio" name="sex" value=0> Female
</label>
</div>
</div>
<div class="form-group">
<label for="interest" class="col-sm-2 control-label">Interest:</label>
<div class="col-sm-10">
<label class="checkbox-inline">
<input type="checkbox" name="interest" value=0>Books
</label>
<label class="checkbox-inline">
<input type="checkbox" name="interest" value=1>Music
</label>
<label class="checkbox-inline">
<input type="checkbox" name="interest" value="2">Movies
</label>
<label class="checkbox-inline">
<input type="checkbox" name="interest" value="3">Sports
</label>
<label class="checkbox-inline">
<input type="checkbox" name="interest" value="4">Travel
</label>
</div>
</div>
<div class="form-group">
<label for="introduction" class="col-sm-2 control-label">Introduction:</label>
<div class="col-sm-10">
<textarea name="introduction" class="form-control" rows="4"></textarea>
</div>
</div>
<div class="form-group">
<div class="col-sm-offset-2 col-sm-10">
<button type="submit" class="btn btn-success">Sign up</button>
</div>
</div>
</form>
<script src="http://code.jquery.com/jquery-latest.js"></script>
<script>
$(function() {
var data = {
username: "Ross",
password: "123456",
education: 2,
sex: 1,
interest: [0, 1, 4],
introduction: "My name is Rosste"
};
//set value when form type is "text"、"password"、"hidden"、"textarea"
$("input[name='username']").val(data.username);
$("input[name='password']").val(data.password);
$("textarea").val(data.introduction);
//set select value
$("select[name='education']").val(data.education);
//set radio checked by value
$("input[name='sex'][value=" + data.sex + "]").prop('checked', true);
//set radio checked by index
// $("input[name='sex']").eq(0).prop('checked', true);
//set checkbox group checked from checked array
$("input[name='interest']").each(function(index, item) {
$(this).prop("checked", $.inArray(parseInt($(this).val()), data.interest) !== -1)
})
//set checkbox checked by value
// $("input[name='interest']").eq(0).prop('checked', true);
//set checkbox checked by value
// $("input[name='interest'][value=3]").prop('checked', true);
$("button").on("click", function(event) {
//prevent it from submitting a form
event.preventDefault();
//get value when form type is "text"、"password"、"hidden"、"textarea"
console.log($("input[type='text']").val(), "username")
console.log($("input[type='password']").val(), "password")
console.log($("textarea").val(), "introduction")
//get select value
console.log($("select").val(), "education")
//get select text
// console.log($("select option:selected").text(),"education text")
//get checked value
console.log($("input[type='radio']:checked").val(), "Sex");
//get checked array from checkbox group
var checkboxList = [];
$("input[type='checkbox']:checked").each(function(index, item) {
checkboxList.push(parseInt($(this).val()));
console.log(checkboxList, "checkboxList");
})
//serialize the form for ajax to send to backend
console.log(decodeURIComponent($('form').serialize()), "serialize")
})
})
</script>
</body>
</html>
