web开发常用js功能性小技巧
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<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN">; 
<HTML>; 
<HEAD>; 
<TITLE>; New Document </TITLE>; 
</HEAD>;
<BODY>; 
<FORM METHOD=POST ACTION="">; 
<input οnpaste="return false;" type="text" name="textfield" style="width:400px;  ime-mode:disabled" value=" English only">;  
</FORM>; 
</BODY>; 
</HTML>; 
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只能输入数字 
<script LANGUAGE="javascript">; 
<!-- 
function check() 
{ 
if (document.form.tell.value==""){ 
 alert("請輸入電話號碼!"); 
 document.form.tell.focus(); 
 return false; 
} 
else{ 
 var Letters = "0123456789()+-"; 
 for (i=0; i< document.form.tell.value.length; i++){ 
    var CheckChar = document.form.tell.value.charAt(i); 
    if (Letters.indexOf(CheckChar) == -1){ 
      alert("電話號碼格式不正確!"); 
      document.form.tell.focus(); 
      return false; 
     } 
   } 
 } 
} 
//-->; 
</script>;  
在<body>;...</body>;之间的表单. 
<form method="POST" name=form action="" onSubmit="return check();">; 
<p align="center">; 
  请输入电话号码:<input type="text" name="tell" size="20">; 
<input type="submit" value="提交" name="B1">;</p>; 
</form>; 
  
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e mail 合法性检查 
function check() 
{ 
if(document.register.email.value.length!=0) 
 { 
   if (document.register.email.value.charAt(0)=="." ||         
        document.register.email.value.charAt(0)=="@"||        
        document.register.email.value.indexOf('@', 0) == -1 ||  
        document.register.email.value.indexOf('.', 0) == -1 ||  
        document.register.email.value.lastIndexOf("@")                           
     ==document.register.email.value.length-1 ||  
        document.register.email.value.lastIndexOf(".") 
             ==document.register.email.value.length-1) 
    { 
     alert("Email的格式不正確!"); 
     document.register.email.focus(); 
     return false; 
     } 
  } 
else 
 { 
  alert("Email的不能为空!"); 
  document.register.email.focus(); 
  return false; 
  } 
return false; 
}  
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页面右键屏蔽 
<body οncοntextmenu="return false">; 
---------------------------------------------------------------- 
自动清除输入框中的空格 
再<head>;...</head>;间加入  
<SCRIPT LANGUAGE="JavaScript">; 
<!--// 
function ignoreSpaces(string) { 
var temp = ""; 
string = '' + string; 
splitstring = string.split(" "); //双引号之间是个空格; 
for(i = 0; i < splitstring.length; i++) 
temp += splitstring; 
return temp; 
} 
//-->; 
</script>;  
如下代码加入<body>;区
<form method="post" action="...">; 
<input type=text size=25 onBlur="this.value=ignoreSpaces(this.value);" name="text">; 
<input type=submit value="Ok" name="button">; 
</form>;   
  
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右键菜单的淡入淡出效果 
<HTML>;<HEAD>;<TITLE>;右键菜单的淡入淡出效果</TITLE>; 
<META content="text/html; charset=gb2312" http-equiv=Content-Type>; 
<SCRIPT language=JavaScript>; 
<!-- // RightClickMenu 
var intDelay=10; //设置菜单显示速度,越大越慢 
var intInterval=5; //每次更改的透明度  
function showmenuie5(){ 
var rightedge=document.body.clientWidth-event.clientX 
var bottomedge=document.body.clientHeight-event.clientY 
if (rightedge<ie5menu.offsetWidth) 
ie5menu.style.left=document.body.scrollLeft+event.clientX-ie5menu.offsetWidth 
else 
ie5menu.style.left=document.body.scrollLeft+event.clientX 
if (bottomedge<ie5menu.offsetHeight) 
ie5menu.style.top=document.body.scrollTop+event.clientY-ie5menu.offsetHeight 
else 
ie5menu.style.top=document.body.scrollTop+event.clientY 
ie5menu.style.visibility="visible" 
//ie5menu.style.visibility="" 
ie5menu.filters.alpha.opacity=0 
GradientShow() 
return false 
} 
function hidemenuie5(){ 
//ie5menu.style.visibility="hidden" 
GradientClose() 
} 
function highlightie5(){ 
if (event.srcElement.className=="menuitems"){ 
event.srcElement.style.backgroundColor="highlight" 
event.srcElement.style.color="white" 
} 
} 
function lowlightie5(){ 
if (event.srcElement.className=="menuitems"){ 
event.srcElement.style.backgroundColor="" 
event.srcElement.style.color="#000000" 
} 
}  
function jumptoie5(){ 
if (event.srcElement.className=="menuitems"){ 
if (event.srcElement.url != ''){ 
if (event.srcElement.getAttribute("target")!=null) 
window.open(event.srcElement.url,event.srcElement.getAttribute("target")) 
else 
window.location=event.srcElement.url 
} 
} 
}  
function GradientShow() //实现淡入的函数  
{  
ie5menu.filters.alpha.opacity+=intInterval  
if (ie5menu.filters.alpha.opacity<100) setTimeout("GradientShow()",intDelay) 
}  
function GradientClose() //实现淡出的函数  
{  
ie5menu.filters.alpha.opacity-=intInterval  
if (ie5menu.filters.alpha.opacity>;0) {  
 setTimeout("GradientClose()",intDelay)  
 }  
else {  
 ie5menu.style.visibility="hidden" 
 }  
}  
function ChangeBG() //改变菜单项的背景颜色,这里的两种颜色值可以改为你需要的  
{  
oEl=event.srcElement  
if (oEl.style.background!="navy") {  
  oEl.style.background="navy"  
  }  
  else {  
  oEl.style.background="#cccccc"  
  }  
}  
// -->; 
</SCRIPT>;  
<style type=text/css>; 
.cMenu { 
FILTER: alpha(opacity=0);BACKGROUND-COLOR: #D6D3CE;BORDER-BOTTOM: #666666 2px solid; BORDER-LEFT: #E4E4E4 2px solid; BORDER-RIGHT: #666666 2px solid; BORDER-TOP: #E4E4E4 2px solid; COLOR: #000000; CURSOR: default; FONT-SIZE: 9pt; color:#000000;FONT-WEIGHT: normal; LINE-HEIGHT: 20px; POSITION: absolute; VISIBILITY: hidden; WIDTH: 110px 
} 
.menuitems { 
font-size:9pt; 
MARGIN: 2px; 
PADDING-BOTTOM: 0px; 
   PADDING-LEFT: 15px; 
   PADDING-RIGHT: 3px; 
   PADDING-TOP: 0px; 
} 
</style>;  
<META content="Microsoft FrontPage 4.0" name=GENERATOR>; 
</HEAD>; 
<BODY>; 
<OBJECT classid=CLSID:8856F961-340A-11D0-A96B-00C04FD705A2 height=0 id=WebBrowser width=0>; 
</OBJECT>; 
<RIGHTCLICK>;<!--[if IE]>; 
<DIV class=cMenu id=ie5menu οnclick=jumptoie5() οnmοuseοut=lowlightie5()  
οnmοuseοver=highlightie5()>;  
<DIV class=menuitems url="javascript:click_obj(0)">;后退</DIV>; 
<DIV class=menuitems url="javascript:click_obj(1)">;前进</DIV>; 
<DIV class=menuhr>;<hr style="width:100%">;</DIV>; 
<DIV class=menuitems url="javascript:click_obj(2)">;刷新</DIV>; 
<DIV class=menuitems url="javascript:click_obj(3)">;加入收藏夹</DIV>; 
<DIV class=menuitems url="javascript:click_obj(4)">;查看源文件</DIV>; 
<DIV class=menuhr>;<hr style="width:100%">;</DIV>; 
<DIV class=menuitems url="javascript:click_obj(5)">;属性</DIV>;  
</DIV>; 
<![endif]-->;  
<SCRIPT language=JavaScript>; 
<!-- 
function click_obj(id){ 
switch(id){ 
case 0:  
history.back() 
break 
case 1: 
history.forward() 
break 
case 2: 
window.location.reload() 
break 
case 3: 
window.external.AddFavorite(location.href, document.title) 
break 
case 4: 
window.location = "view-source:" + window.location.href 
break 
case 5: 
document.all.WebBrowser.ExecWB(10,1) 
break 
} 
}  
if (document.all&&window.print){ 
ie5menu.className="cMenu" 
document.οncοntextmenu=showmenuie5 
document.body.οnclick=hidemenuie5 
} 
//-->; 
</SCRIPT>; 
</RIGHTCLICK>; 
</BODY>;</HTML>; 
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ie用activex实现打印  我没有检测过版本,ie6下正常 
<head>;...</head>;加入: 
<SCRIPT LANGUAGE=javascript>; 
<!-- 
function setPrint() 
{ 
WB.ExecWB(8,1); 
} 
function previewPrint() 
{ 
WB.ExecWB(7,1) 
} 
//-->; 
</SCRIPT>; 
在<body>;...</body>;加入: 
<OBJECT classid=CLSID:8856F961-340A-11D0-A96B-00C04FD705A2 height=0 id=WB width=0>; 
</OBJECT>; 
<INPUT type="button" value="Set" id=button1 name=button1 οnclick="setPrint();">; 
<INPUT type="button" value="Preview" id=button2 name=button2 οnclick="previewPrint();">;  
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超链接提交表单  
<script LANGUAGE="JavaScript">; 
function checkvalue() 
{ 
 if(document.welcomeform.nickname.value=="") 
 { 
  alert("昵称不能为空!"); 
  return(false); 
  } 
 if(document.welcomeform.password.value=="") 
 { 
  alert("密码不能为空!"); 
  return(false);     
  } 
 document.welcomeform.submit();  
 return(true);    
} 
</script>; 
在<body>;...</body>;之间加入如下代码: 
<form name="welcomeform" method="post" action="welcome.asp">; 
 <a href="#" οnclick="javascript:checkvalue();return false:">;登录</a>; 
</form>;  
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不允许缓存页面 
使用java提供的方法,在jsp或者servlet中都可以 
<%  
response.setHeader("Pragma","No-cache");  
response.setHeader("Cache-Control","no-cache");  
response.setDateHeader("Expires", 0);  
%>;   
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