javascript技巧大全 (3)-优快云博客

本文介绍了如何在JavaScript中自定义实现Function.prototype.apply和Function.prototype.call方法，以及使用ActiveX对象进行文件下载、连接数据库、读取数据等操作。

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//自定义的apply,call

Function.prototype.apply = function (obj, argu) {
if (obj) obj.constructor.prototype._caller = this;
var argus = new Array();
for (var i=0;i<argu.length;i++)
argus[i] = "argu[" + i + "]";
var r;
eval("r = " + (obj ? ("obj._caller(" + argus.join(",") + ");") : ("this(" + argus.join(",") + ");")));
return r;
};
Function.prototype.call = function (obj) {
var argu = new Array();
for (var i=1;i<arguments.length;i++)
argu[i-1] = arguments[i];
return this.apply(obj, argu);
};

//下载文件

function DownURL(strRemoteURL,strLocalURL)
{
try
{
var xmlHTTP=new ActiveXObject("Microsoft.XMLHTTP");
xmlHTTP.open("Get",strRemoteURL,false);
xmlHTTP.send();
var adodbStream=new ActiveXObject("ADODB.Stream");
adodbStream.Type=1;//1=adTypeBinary
adodbStream.Open();
adodbStream.write(xmlHTTP.responseBody);
adodbStream.SaveToFile(strLocalURL,2);
adodbStream.Close();
adodbStream=null;
xmlHTTP=null;

}
catch(e)
{
window.confirm("下载URL出错!");
}
//window.confirm("下载完成.");
}

//检验连接是否有效

//组件是否安装
isComponentInstalled("{6B053A4B-A7EC-4D3D-4567-B8FF8A1A5739}", "componentID"))

//检查网页是否存在

function Checkurl(/URL)
{
var xmlhttp = new ActiveXObject("Microsoft.XMLHTTP");
xmlhttp.Open("GET",URL, false);
try
{
    xmlhttp.Send();
    var result = xmlhttp.status;
}
catch(e) {return(false); }
if(result==200)
{
    return true;
}
xmlhttp = null;
return false;
}
//连接数据库

<script language="javascript">
//用 JavaScript 写服务器端连接数据库的代码示例
var conn = new ActiveXObject("ADODB.Connection");
conn.Open("Provider=SQLOLEDB.1; Data Source=localhost; User ID=sa; "
    +"Password=; Initial Catalog=pubs");
var rs = new ActiveXObject("ADODB.Recordset");
var sql="select * from authors";
rs.open(sql, conn);
shtml = "<table width='100%' border=1>";
shtml +="<tr bgcolor='#f4f4f4'><td>au_id</td><td>au_lname</td><td>au_fname</td><td>phone</td><td>address</td><td> city</td><td>state</td><td>zip</td></tr>";
while(!rs.EOF)
{
shtml += "<tr><td>" + rs("au_id") + "</td><td>" + rs("au_lname") + "</td><td>" + rs("au_fname") + "</td><td>" + rs("phone") + "</td><td>" + rs("address") + "</td><td>" + rs("city") + "</td><td>" + rs("state") + "</td><td>" + rs("zip") + "</td></tr>";
rs.moveNext;
}
shtml += "</table>";
document.write(shtml);
rs.close();
rs = null;
conn.close();
conn = null;
</script>
//使用数据岛

<html>
<body>
srno：<input type=text datasrc=#xmldate DataFLD=srno size="76"><BR>
times：<input type=text datasrc=#xmldate DataFLD=times size="76"><BR>
<input id="first" TYPE=button value="<<　第一条记录" onclick="xmldate.recordset.moveFirst()">
<input id="prev" TYPE=button value="<上一条记录" onclick="xmldate.recordset.movePrevious()">
<input id="next" TYPE=button value="下一条记录>" onclick="xmldate.recordset.moveNext()">
<input id="last" TYPE=button value="最后一条记录>>" onclick="xmldate.recordset.moveLast()">
<input id="Add" TYPE=button value="添加新记录" onclick="xmldate.recordset.addNew()">

<XML ID="xmldate">
<infolist>
<info ><srno>20041025-01</srno><times>null</times></info>
<info ><srno>20041101-09</srno><times>2004年10月1日2点22分0秒</times></info>
</infolist>
</XML>
</body>
</html>
//获得参数

<body>
<a href="/"javascript:location.href="/location.href ";+ '?a=1&b=2'">search</a>
<script language="JavaScript">

</script>
</body>
//可编辑SELECT

<input type=text name=re_name style="width:100px;height:21px;font-size:10pt;"><span style="width:18px;border:0px solid red;"><select name="r00" style="margin-left:-100px;width:118px; background-color:#FFEEEE;" onChange="document.all.re_name.value=this.value;">
                <option value="1">11111111<option>
                <option value="2">222222</option>
                <option value="3">333333</option>
              </select>
              </span>
//设置光标位置

function getCaret(textbox)
{
var

function getXML(URL)
{
var xmlhttp = new ActiveXObject("microsoft.xmlhttp");
xmlhttp.Open("GET",URL, false);
try
{
xmlhttp.Send();
}
catch(e){}
finally
{
var result = xmlhttp.responseText;
if(result)
{
   if(xmlhttp.Status==200)
   {
    return(true);
   }
   else
   {
    return(false);
   }
}
else
{
   return(false);
}
}
}
//POST代替FORM

<SCRIPT language="VBScript">
Function URLEncoding(vstrIn)
    strReturn = ""
    For i = 1 To Len(vstrIn)
        ThisChr = Mid(vStrIn,i,1)
        If Abs(Asc(ThisChr)) < &HFF Then
            strReturn = strReturn & ThisChr
        Else
            innerCode = Asc(ThisChr)
            If innerCode < 0 Then
                innerCode = innerCode + &H10000
            End If
            Hight8 = (innerCode And &HFF00)\ &HFF
            Low8 = innerCode And &HFF
            strReturn = strReturn & "%" & Hex(Hight8) & "%" & Hex(Low8)
        End If
    Next
    URLEncoding = strReturn
End Function
Function bytes2BSTR(vIn)
    strReturn = ""
    For i = 1 To LenB(vIn)
        ThisCharCode = AscB(MidB(vIn,i,1))
        If ThisCharCode < &H80 Then
            strReturn = strReturn & Chr(ThisCharCode)
        Else
            NextCharCode = AscB(MidB(vIn,i+1,1))
            strReturn = strReturn & Chr(CLng(ThisCharCode) * &H100 + CInt(NextCharCode))
            i = i + 1
        End If
    Next
    bytes2BSTR = strReturn
End Function
dim strA,oReq
strA = URLEncoding("submit1=Submit&text1=中文")
set oReq = CreateObject("MSXML2.XMLHTTP")
oReq.open "POST","http://ServerName/VDir/TstResult.asp",false
oReq.setRequestHeader "Content-Length",Len(strA)
oReq.setRequestHeader "CONTENT-TYPE","application/x-www-form-urlencoded"
oReq.send strA
msgbox bytes2BSTR(oReq.responseBody)
</SCRIPT>
//readyState是xmlhttp返回数据的进度，0=载入中,1=未初始化,2=已载入,3=运行中,4=完成

转载于:https://my.oschina.net/darkness/blog/802869