发布于 2017-06-29 05:48:43 | 61 次阅读 | 评论: 0 | 来源: 网友投递

这里有新鲜出炉的Javascript教程，程序狗速度看过来！

JavaScript客户端脚本语言

Javascript 是一种由Netscape的LiveScript发展而来的原型化继承的基于对象的动态类型的区分大小写的客户端脚本语言，主要目的是为了解决服务器端语言，比如Perl，遗留的速度问题，为客户提供更流畅的浏览效果。

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这是一篇译文，实例分析制作自定义的信息提示框的实现代码
本文制作一个用户自定义的AlertBox,效果如图:

js文件中插入如下代码：

// JScript 文件 
// constants to define the title of the alert and button text. 
var ALERT_TITLE = "Oops!"; 
var ALERT_BUTTON_TEXT = "Close"; 
// over-ride the alert method only if this a newer browser. 
// Older browser will see standard alerts 
if(document.getElementById) { 
window.alert = function(txt) { 
createCustomAlert(txt); 
} 
} 
function createCustomAlert(txt) { 
// shortcut reference to the document object 
d = document; 
// if the modalContainer object already exists in the DOM, bail out. 
if(d.getElementById("modalContainer")) return; 
// create the modalContainer div as a child of the BODY element 
mObj = d.getElementsByTagName("body")[0].appendChild(d.createElement("div")); 
mObj.id = "modalContainer"; 
// make sure its as tall as it needs to be to overlay all the content on the page 
mObj.style.height = document.documentElement.scrollHeight + "px"; 
// create the DIV that will be the alert 
alertObj = mObj.appendChild(d.createElement("div")); 
alertObj.id = "alertBox"; 
// MSIE doesnt treat position:fixed correctly, so this compensates for positioning the alert 
if(d.all && !window.opera) alertObj.style.top = document.documentElement.scrollTop + "px"; 
// center the alert box 
alertObj.style.left = (d.documentElement.scrollWidth - alertObj.offsetWidth)/2 + "px"; 
// create an H1 element as the title bar 
h1 = alertObj.appendChild(d.createElement("h1")); 
h1.appendChild(d.createTextNode(ALERT_TITLE)); 
// create a paragraph element to contain the txt argument 
msg = alertObj.appendChild(d.createElement("p")); 
msg.innerHTML = txt; 
// create an anchor element to use as the confirmation button. 
btn = alertObj.appendChild(d.createElement("a")); 
btn.id = "closeBtn"; 
btn.appendChild(d.createTextNode(ALERT_BUTTON_TEXT)); 
btn.href = "#"; 
// set up the onclick event to remove the alert when the anchor is clicked 
btn.onclick = function() { removeCustomAlert();return false; } 
// removes the custom alert from the DOM function removeCustomAlert() { 
// document.getElementsByTagName("body")[0].removeChild(document.getElementById("modalContainer")); 
} 
// removes the custom alert from the DOM 
function removeCustomAlert() 
{ 
document.getElementsByTagName("body")[0].removeChild(document.getElementById("modalContainer")); 
} 

将如下代码粘贴到你的HTML你的HTML的HEAD部分。 

<script type="text/javascript" src="include/customAlertBox.js"></script> 
<!-- Paste this code into your external style sheet or the 
CSS section of your HTML document --> 
<style type="text/css"> 
#modalContainer { 
background-color:transparent; 
position:absolute; 
width:100%; 
height:100%; 
top:0px; 
left:0px; 
z-index:10000; 
} 
#alertBox { 
position:relative; 
width:300px; 
min-height:100px; 
margin-top:50px; 
border:2px solid #000; 
background-color:#F2F5F6; 
background-image:url(alert.png); 
background-repeat:no-repeat; 
background-position:20px 30px; 
} 
#modalContainer > #alertBox { 
position:fixed; 
} 
#alertBox h1 { 
margin:0; 
font:bold 0.9em verdana,arial; 
background-color:#78919B; 
color:#FFF; 
border-bottom:1px solid #000; 
padding:2px 0 2px 5px; 
} 
#alertBox p { 
font:0.7em verdana,arial; 
height:50px; 
padding-left:5px; 
margin-left:55px; 
} 
#alertBox #closeBtn { 
display:block; 
position:relative; 
margin:5px auto; 
padding:3px; 
border:1px solid #000; 
width:70px; 
font:0.7em verdana,arial; 
text-transform:uppercase; 
text-align:center; 
color:#FFF; 
background-color:#78919B; 
text-decoration:none; 
} 
</style>

在你的HTML文档的Body部分插入如下代码:

<input type="button" value = "Test the alert" onclick="alert('This is a custom alert dialog that was created by overriding the window.alert method.');">