javascript重写alert方法的实例代码
作者：
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
<title>重写alert</title>
<link href="css/style.css" rel="stylesheet"/>
<script type="text/javascript" src="http://ajax.googleapis.com/ajax/libs/jquery/1.5.2/jquery.min.js"></script>
<script type="text/javascript">
var showAlert = function(msg){
jAlert(msg, "提示！");
}
window.alert=showAlert;
$.alerts={
verticalOffset:-75,horizontalOffset:0,repositionOnResize:true,overlayOpacity:.01,overlayColor:'#FFF',draggable:true,okButton:' OK ',cancelButton:' Cancel ',dialogClass:null,alert:function(message,title,callback){
if(title==null)title='Alert';
$.alerts._show(title,message,null,'alert',function(result){
if(callback)callback(result)
})
}
,_show:function(title,msg,value,type,callback){
$.alerts._hide();
$.alerts._overlay('show');
$("BODY").append('<div id="popup_container">'+'<h1 id="popup_title"></h1>'+'<div id="popup_content">'+'<div id="popup_message"></div>'+'</div>'+'</div>');
if($.alerts.dialogClass)$("#popup_container").addClass($.alerts.dialogClass);
var pos=($.browser.msie&&parseInt($.browser.version)<=6)?'absolute':'fixed';
$("#popup_container").css({
position:pos,zIndex:99999,padding:0,margin:0
});
$("#popup_title").text(title);
$("#popup_content").addClass(type);
$("#popup_message").text(msg);
$("#popup_message").html($("#popup_message").text().replace(/\n/g,'<br />'));
$("#popup_container").css({
minWidth:$("#popup_container").outerWidth(),maxWidth:$("#popup_container").outerWidth()
});
$.alerts._reposition();
$.alerts._maintainPosition(true);
switch(type){
case'alert':$("#popup_message").after('<div id="popup_panel"><input type="button" value="'+$.alerts.okButton+'" id="popup_ok" /></div>');
$("#popup_ok").click(function(){
$.alerts._hide();
callback(true)
});
$("#popup_ok").focus().keypress(function(e){
if(e.keyCode==13||e.keyCode==27)$("#popup_ok").trigger('click')
});
break
};
if($.alerts.draggable){
try{
$("#popup_container").draggable({
handle:$("#popup_title")
});
$("#popup_title").css({
cursor:'move'
})
}
catch(e){}
}
}
,_hide:function(){
$("#popup_container").remove();
$.alerts._overlay('hide');
$.alerts._maintainPosition(false)
}
,_overlay:function(status){
switch(status){
case'show':$.alerts._overlay('hide');
$("BODY").append('<div id="popup_overlay"></div>');
$("#popup_overlay").css({
position:'absolute',zIndex:99998,top:'0px',left:'0px',width:'100%',height:$(document).height(),background:$.alerts.overlayColor,opacity:$.alerts.overlayOpacity
});
break;
case'hide':$("#popup_overlay").remove();
break
}
}
,_reposition:function(){
var top=(($(window).height()/ 2) - ($("#popup_container").outerHeight() /2))+$.alerts.verticalOffset;
var left=(($(window).width()/ 2) - ($("#popup_container").outerWidth() /2))+$.alerts.horizontalOffset;
if(top<0)top=0;
if(left<0)left=0;
if($.browser.msie&&parseInt($.browser.version)<=6)top=top+$(window).scrollTop();
$("#popup_container").css({
top:top+'px',left:left+'px'
});
$("#popup_overlay").height($(document).height())
}
,_maintainPosition:function(status){
if($.alerts.repositionOnResize){
switch(status){
case true:$(window).bind('resize',function(){
$.alerts._reposition()
});
break;
case false:$(window).unbind('resize');
break
}
}
}
};
jAlert=function(message,title,callback){
$.alerts.alert(message,title,callback)
}
$(function(){alert("hello word！")})
</script>
<style>
#popup_container{font-family:Arial,sans-serif;font-size:12px;min-width:300px;max-width:600px;background:#FFF;border:solid 5px #999;color:#000;-moz-border-radius:5px;-webkit-border-radius:5px;border-radius:5px;}#popup_title{font-size:14px;font-weight:bold;text-align:center;line-height:1.75em;color:#666;background:#CCC url(images/title.gif) top repeat-x;border:solid 1px #FFF;border-bottom:solid 1px #999;cursor:default;padding:0em;margin:0em;}#popup_content{background:16px 16px no-repeat url(images/info.gif);padding:1em 1.75em;margin:0em;}#popup_content.alert{background-image:url(images/info.gif);}#popup_message{padding-left:48px;}#popup_panel{text-align:center;margin:1em 0em 0em 1em;}#popup_prompt{margin:.5em 0em;}
</style>
</head>
<body>
</body>
</html>