The bubbling event is to click on the child node, which will trigger the click event of the parent node and the ancestor node upward.
Here is the html code part:
<body>
<div id="content">
outer div element
<span>Inner span element</span>
outer div element
</div>
<div id="msg"></div>
</body>
The corresponding jQuery code is as follows:
<script type="text/javascript">
$(function(){
// Bind the click event for the span element
$('span').bind("click",function(){
var txt = $('#msg').html() + "<p>The inner span element is clicked.<p/>";//Get html information
$('#msg').html(txt);// Set html information
});
// bind the click event to the div element
$('#content').bind("click",function(){
var txt = $('#msg').html() + "<p>The outer div element is clicked.<p/>";
$('#msg').html(txt);
});
// Bind the click event to the body element
$("body").bind("click",function(){
var txt = $('#msg').html() + "<p>body element was clicked.<p/>";
$('#msg').html(txt);
});
})
</script>
When the span is clicked, the click event of the div and body will be triggered. When the div is clicked, the body's click event is fired.
How to prevent this bubbling event from happening?
Modify as follows:
<script type="text/javascript">
$(function(){
// Bind the click event for the span element
$('span').bind("click",function(event){
var txt = $('#msg').html() + "<p>The inner span element is clicked.<p/>";
$('#msg').html(txt);
event.stopPropagation(); // stop event from bubbling
});
// bind the click event to the div element
$('#content').bind("click",function(event){
var txt = $('#msg').html() + "<p>The outer div element is clicked.<p/>";
$('#msg').html(txt);
event.stopPropagation(); // stop event from bubbling
});
// Bind the click event to the body element
$("body").bind("click",function(){
var txt = $('#msg').html() + "<p>body element was clicked.<p/>";
$('#msg').html(txt);
});
})
</script>
event.stopPropagation(); // stop event from bubbling
有时候点击提交按钮会有一些默认事件。比如跳转到别的界面。但是如果没有通过验证的话，就不应该跳转。这时候可以通过设置event.preventDefault(); //阻止默认行为 ( 表单提交 )。
下面是案例：
<script type="text/javascript">
$(function(){
$("#sub").bind("click",function(event){
var username = $("#username").val(); //获取元素的值，val() 方法返回或设置被选元素的值。
if(username==""){ //判断值是否为空
$("#msg").html("<p>文本框的值不能为空.</p>"); //提示信息
event.preventDefault(); //阻止默认行为 ( 表单提交 )
}
})
})
</script>
html部分：
<body> <form action="test.html"> 用户名：<input type="text" id="username" /> <br/> <input type="submit" value="提交" id="sub"/> </form> <div id="msg"></div> </body>
还有一种防止默认行为的方法就是return false。效果一样。
代码如下：
<script type="text/javascript">
$(function(){
$("#sub").bind("click",function(event){
var username = $("#username").val(); //获取元素的值
if(username==""){ //判断值是否为空
$("#msg").html("<p>文本框的值不能为空.</p>"); //提示信息
return false;
}
})
})
</script>
同理，上面的冒泡事件也可以通过return false来处理。
<script type="text/javascript">
$(function(){
// 为span元素绑定click事件
$('span').bind("click",function(event){
var txt = $('#msg').html() + "<p>内层span元素被点击.<p/>";
$('#msg').html(txt);
return false;
});
// 为div元素绑定click事件
$('#content').bind("click",function(event){
var txt = $('#msg').html() + "<p>外层div元素被点击.<p/>";
$('#msg').html(txt);
return false;
});
// 为body元素绑定click事件
$("body").bind("click",function(){
var txt = $('#msg').html() + "<p>body元素被点击.<p/>";
$('#msg').html(txt);
});
})
</script>