📄 js_events.asp
字号:
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html lang="en-US" xml:lang="en-US" xmlns="http://www.w3.org/1999/xhtml">
<head>
<title>JavaScript Events</title>
<link rel="shortcut icon" href="../favicon.ico" type="image/x-icon" />
<meta http-equiv="Content-Type" content="text/html; charset=ISO-8859-1" />
<meta name="Keywords" content="xml,tutorial,html,dhtml,css,xsl,xhtml,javascript,asp,ado,vbscript,dom,sql,colors,soap,php,authoring,programming,training,learning,beginner's guide,primer,lessons,school,howto,reference,examples,samples,source code,tags,demos,tips,links,FAQ,tag list,forms,frames,color table,w3c,cascading style sheets,active server pages,dynamic html,internet,database,development,Web building,Webmaster,html guide" />
<meta name="Description" content="Free HTML XHTML CSS JavaScript DHTML XML DOM XSL XSLT RSS AJAX ASP ADO PHP SQL tutorials, references, examples for web building." />
<meta http-equiv="pragma" content="no-cache" />
<meta http-equiv="cache-control" content="no-cache" />
<link rel="stylesheet" type="text/css" href="../stdtheme.css" />
<script type="text/javascript">
var gaJsHost = (("https:" == document.location.protocol) ? "../../https@ssl./default.htm" : "../../www./default.htm");
document.write(unescape("%3Cscript src='" + gaJsHost + "google-analytics.com/ga.js' type='text/javascript'%3E%3C/script%3E"));
</script>
<script type="text/javascript">
var pageTracker = _gat._getTracker("UA-3855518-1");
pageTracker._initData();
pageTracker._trackPageview();
</script>
</head>
<body>
<a name="top"></a>
<table cellpadding="0" cellspacing="0" width="100%" bgcolor="#808080">
<tr>
<td width="234" valign="top">
<a href="../default.htm"><img src="../images/w3default80.jpg" border="0" alt="W3Schools" /></a>
</td>
<th valign="middle" align="left" class="right">
<iframe style="background-color:#808080" src="../banners/bannerframe.asp@adpartner=xmlmaster" height="90" width="728"
marginwidth="0" marginheight="0" frameborder="0" scrolling="no">
Your browser does not support inline frames or is currently configured not to display inline frames.
</iframe>
<br /></th>
</tr>
</table>
<table style="margin-left:1px" width="800px" border="0" cellpadding="0" cellspacing="2">
<tr>
<td width="137" class="content" valign="top"><br />
<a class="left" href="../default.asp" target="_top">
<img src="../images/homeicon.gif" border="0" alt="home" /></a>
<a class="left" href="../default.asp" target="_top">
<b>HOME</b></a>
<br /><br />
<b>JS Basic</b>
<br />
<a class="left" target="_top" href="default.asp" >JS HOME</a><br />
<a class="left" target="_top" href="js_intro.asp" >JS Introduction</a><br />
<a class="left" target="_top" href="js_howto.asp" >JS How To</a><br />
<a class="left" target="_top" href="js_whereto.asp" >JS Where To</a><br />
<a class="left" target="_top" href="js_statements.asp" >JS Statements</a><br />
<a class="left" target="_top" href="js_comments.asp" >JS Comments</a><br />
<a class="left" target="_top" href="js_variables.asp" >JS Variables</a><br />
<a class="left" target="_top" href="js_operators.asp" >JS Operators</a><br />
<a class="left" target="_top" href="js_comparisons.asp" >JS Comparisons</a><br />
<a class="left" target="_top" href="js_if_else.asp" >JS If...Else</a><br />
<a class="left" target="_top" href="js_switch.asp" >JS Switch</a><br />
<a class="left" target="_top" href="js_popup.asp" >JS Popup Boxes</a><br />
<a class="left" target="_top" href="js_functions.asp" >JS Functions</a><br />
<a class="left" target="_top" href="js_loop_for.asp" >JS For Loop</a><br />
<a class="left" target="_top" href="js_loop_while.asp" >JS While Loop</a><br />
<a class="left" target="_top" href="js_break.asp" >JS Break Loops</a><br />
<a class="left" target="_top" href="js_loop_for_in.asp" >JS For...In</a><br />
<a class="left" target="_top" href="js_events.asp" style='font-weight:bold;'>JS Events</a><br />
<a class="left" target="_top" href="js_try_catch.asp" >JS Try...Catch</a><br />
<a class="left" target="_top" href="js_throw.asp" >JS Throw</a><br />
<a class="left" target="_top" href="js_onerror.asp" >JS onerror</a><br />
<a class="left" target="_top" href="js_special_characters.asp" >JS Special Text</a><br />
<a class="left" target="_top" href="js_guidelines.asp" >JS Guidelines</a><br />
<br />
<b>JS Objects</b>
<br />
<a class="left" target="_top" href="js_obj_intro.asp" >JS Objects Intro</a><br />
<a class="left" target="_top" href="js_obj_string.asp" >JS String</a><br />
<a class="left" target="_top" href="js_obj_date.asp" >JS Date</a><br />
<a class="left" target="_top" href="js_obj_array.asp" >JS Array</a><br />
<a class="left" target="_top" href="js_obj_boolean.asp" >JS Boolean</a><br />
<a class="left" target="_top" href="js_obj_math.asp" >JS Math</a><br />
<a class="left" target="_top" href="js_obj_regexp.asp" >JS RegExp</a><br />
<a class="left" target="_top" href="js_obj_htmldom.asp" >JS HTML DOM</a><br />
<br />
<b>JS Advanced</b>
<br />
<a class="left" target="_top" href="js_browser.asp" >JS Browser</a><br />
<a class="left" target="_top" href="js_cookies.asp" >JS Cookies</a><br />
<a class="left" target="_top" href="js_form_validation.asp" >JS Validation</a><br />
<a class="left" target="_top" href="js_animation.asp" >JS Animation</a><br />
<a class="left" target="_top" href="js_image_maps.asp" >JS Image Maps</a><br />
<a class="left" target="_top" href="js_timing.asp" >JS Timing</a><br />
<a class="left" target="_top" href="js_objects.asp" >JS Create Object</a><br />
<a class="left" target="_top" href="js_summary.asp" >JS Summary</a><br />
<br />
<b>Examples/Quiz</b>
<br />
<a class="left" target="_top" href="js_examples.asp" >JS Examples</a><br />
<a class="left" target="_top" href="js_examples_2.asp" >JS Object Examples</a><br />
<a class="left" target="_top" href="js_examples_3.asp" >JS DOM Examples</a><br />
<a class="left" target="_top" href="js_quiz.asp" >JS Quiz</a><br />
<br />
<b>JS References</b>
<br />
<a class="left" target="_top" href="../jsref/default.asp" >JS Objects</a><br />
<a class="left" target="_top" href="../htmldom/dom_reference.asp" >JS HTML DOM</a><br />
<br />
<b>Selected Reading</b><br />
<a class="left" target="_top" href="../browsers/browsers_stats.asp">Web Statistics</a><br />
<a class="left" target="_top" href="../site/site_glossary.asp">Web Glossary</a><br />
<a class="left" target="_top" href="../hosting/default.asp">Web Hosting</a><br />
<a class="left" target="_top" href="../quality/default.asp">Web Quality</a><br /><br />
<a class="left" target="_top" href="../forum/default.asp">W3Schools Forum</a><br /><br />
<a class="left" target="_top" href="../about/about_helping.asp">Helping W3Schools</a><br /><br />
<script type="text/javascript"><!--
google_ad_client = "pub-3440800076797949";
/*LeftLinkUnit*/
google_ad_slot = "4854527104";
google_ad_width = 120;
google_ad_height = 90;
//-->
</script>
<script type="text/javascript"
src="../../pagead2.googlesyndication.com/pagead/show_ads.js">
</script>
</td>
<td valign="top">
<table style="border: 1px solid gray" width="100%" bgcolor="#FFFFFF" border="0" cellpadding="5" cellspacing="0">
<tr>
<td>
<h1>JavaScript Events</h1>
<a href="js_loop_for_in.asp"><img alt="previous" border="0" src="../images/btn_previous.gif" width="100" height="20" /></a>
<a href="js_try_catch.asp"><img alt="next" border="0" src="../images/btn_next.gif" width="100" height="20" /></a>
<hr />
<p class="intro">Events are actions that can be detected by JavaScript.</p>
<hr />
<h2>Events</h2>
<p>By using JavaScript, we have the ability to create dynamic web pages. Events are actions that can be detected by JavaScript.</p>
<p>Every element on a web page has certain events which can trigger JavaScript
functions. For example, we can use the onClick event of a button element to
indicate that a function will run when a user clicks on the button. We define
the events in the HTML tags.</p>
<p>Examples of events:</p>
<ul>
<li>A mouse click</li>
<li>A web page or an image loading</li>
<li>Mousing over a hot spot on the web page</li>
<li>Selecting an input box in an HTML form</li>
<li>Submitting an HTML form</li>
<li>A keystroke </li>
</ul>
<p><b>Note:</b> Events are normally used in combination with functions, and the function
will not be executed before the event occurs!</p>
<p>For a complete reference of the events recognized by JavaScript, go to our
<a href="../jsref/jsref_events.asp">complete Event reference</a>.</p>
<hr />
<h2>onload and onUnload</h2>
<p>The onload and onUnload events are triggered when the user enters or leaves
the page.</p>
<p>The onload event is often used to check the visitor's browser type and
browser version, and load the proper version of the web page based on the
information.</p>
<p>Both the onload and onUnload events are also often used to deal with cookies
that should be set when a user enters or leaves a page. For example, you could have a popup asking
for the user's name upon
his first arrival to your page. The name is then stored in a cookie. Next time the visitor arrives at your page,
you could have another popup saying something like: "Welcome John Doe!".</p>
<hr />
<h2>onFocus, onBlur and onChange</h2>
<p>The onFocus, onBlur and onChange events are often used in combination with validation
of form fields.</p>
<p>Below is an example of how to use the onChange event. The checkEmail()
function will be called whenever the user changes the content of the field:</p>
<table class="ex" cellspacing="0" border="1" width="100%" id="table2">
<tr>
<td>
<pre><input type="text" size="30"
id="email" onchange="checkEmail()"></pre>
</td>
</tr>
</table>
<br />
<hr />
<h2>onSubmit</h2>
<p>The onSubmit event is used to validate ALL form fields
before submitting it.</p>
<p>Below is an example of how to use the onSubmit event. The checkForm()
function will be called when the user clicks the submit button in the form. If the
field values are not accepted, the submit should be
cancelled. The function checkForm() returns either true or false. If it returns true the
form will be submitted, otherwise the submit will be cancelled:</p>
<table class="ex" cellspacing="0" border="1" width="100%" id="table3">
<tr>
<td>
<pre><form method="post" action="xxx.htm"
onsubmit="return checkForm()"></pre>
</td>
</tr>
</table>
<br />
<hr />
<h2>onMouseOver and onMouseOut</h2>
<p>onMouseOver and onMouseOut are often used to create
"animated" buttons.</p>
<p>Below is an example of an onMouseOver event. An alert box appears when an onMouseOver
event is detected:</p>
<table class="ex" cellspacing="0" border="1" width="100%" id="table4">
<tr>
<td>
<pre><a href="http://www.w3schools.com"
onmouseover="alert('An onMouseOver event');return false">
<img src="w3schools.gif" width="100" height="30">
</a></pre>
</td>
</tr>
</table>
<br />
<hr />
<a href="js_loop_for_in.asp"><img alt="previous" border="0" src="../images/btn_previous.gif" width="100" height="20" /></a>
<a href="js_try_catch.asp"><img alt="next" border="0" src="../images/btn_next.gif" width="100" height="20" /></a>
<br />
<hr />
<!-- **** SPOTLIGHTS 1 **** -->
<iframe src="../banners/aspallframe.asp" height="110" width="485"
marginwidth="0" marginheight="0" frameborder="0" scrolling="no">
Your browser does not support inline frames or is currently configured not to display inline frames.
</iframe>
<hr />
<!-- **** SPOTLIGHTS 2 **** -->
<h2>Want To Be A Web Master?</h2>
<p>If you want to be a Web Master, you will have to host your web site with an ISP (Internet Service Provider).</p>
<p>MaximumASP offers seven different configurations of dedicated servers to meet your Windows and .NET hosting needs.
Hosted on our multi-tiered Enterprise Class network, these servers provide the performance, security and reliability
you need to host your high end web sites and applications.
</p>
<p><a target="_blank" href="../../www.maximumasp.com/about/specials.aspx">Visit MaximumASP</a></p>
<hr />
<!-- **** SPOTLIGHTS 3 **** -->
<table cellpadding="0" cellspacing="0"><tr><td width="72"></td><td>
<script type="text/javascript"><!--
google_ad_client = "pub-3440800076797949";
/*txt*/
google_ad_slot = "1699448869";
google_ad_width = 336;
google_ad_height = 280;
//-->
</script>
<script type="text/javascript"
src="../../pagead2.googlesyndication.com/pagead/show_ads.js">
</script>
</td></tr></table>
<hr />
<center>
<script type="text/javascript"><!--
google_ad_client = "pub-3440800076797949";
/*imgtxt*/
google_ad_slot = "8606855891";
google_ad_width = 468;
google_ad_height = 60;
//-->
</script>
<script type="text/javascript"
src="../../pagead2.googlesyndication.com/pagead/show_ads.js">
</script>
</center>
<hr />
<!-- **** END SPOTLIGHTS **** -->
</td></tr>
<tr><td>
<p>Jump to: <a href="#top" target="_top"><b>Top of Page</b></a>
or <a href="../default.asp" target="_top"><b>HOME</b></a> or
<a href='js_events.asp@output=print' target="_blank">
<img src="../images/print.gif" alt="Printer Friendly" border="0" />
<b>Printer friendly page</b></a></p>
<p>W3Schools provides material for training only. We do not warrant the correctness of its contents.
The risk from using it lies entirely with the user.
While using this site, you agree to have read and accepted our
<a href="../about/about_copyright.asp">terms of use</a> and
<a href="../about/about_privacy.asp">privacy policy</a>.
</p>
<p><a href="../about/about_copyright.asp">Copyright 1999-2008</a> by Refsnes Data. All Rights Reserved.</p>
<table border="0" width="100%" cellspacing="0" cellpadding="0"><tr>
<td width="60%" align="left">
<a href="../../validator.w3.org/check@uri=referer" target="_blank">
<img src="../images/vxhtml.gif" alt="Validate" width="88" height="31" border="0" /></a>
<a href="../../jigsaw.w3.org/css-validator/check@uri=referer" target="_blank">
<img src="../images/vcss.gif" alt="Validate" width="88" height="31" border="0" /></a>
<a href="../../www.w3.org/WAI/WCAG1A-Conformance" title="Explanation of Level A Conformance" target="_blank">
<img src="../images/wai.gif" alt="W3C-WAI level A conformance icon" width="88" height="31" border="0" /></a>
</td>
<td>
<a href="../xhtml/xhtml_howto.asp" target="_top">W3Schools was converted to XHTML in December 1999</a>
</td></tr>
</table>
</td></tr>
</table>
</td>
<td width="145" align="center" valign="top">
<iframe style="background-color:#f1f1f1" src="../banners/rightcolumn.asp@secid=js" height="1500" width="147"
marginwidth="0" marginheight="0" frameborder="0" scrolling="no">
</iframe>
</td>
</tr></table>
</body>
</html>⌨️ 快捷键说明
复制代码
Ctrl + C
搜索代码
Ctrl + F
全屏模式
F11
切换主题
Ctrl + Shift + D
显示快捷键
?
增大字号
Ctrl + =
减小字号
Ctrl + -