Ajax real-time local refresh

Ajax for Local Refresh


<script type= "Text/javascript" >
var xmlhttp;
function GetData ()
{
Get the name that the user fills in
var City=document.getelementbyid ("TXT"). Value;
To create an asynchronous call object
Xmlhttp=new ActiveXObject ("Microsoft.XMLHTTP");
Associate an object's state with an event
Xmlhttp.onreadystatechange=statechange;
Load the page you want to link to
xmlHTTP. Open ("POST", "datapage.aspx?city=" +city,true);
Send Request
xmlHTTP. Send ();
}
function StateChange ()
{
To determine whether an asynchronous call has been completed
if (xmlhttp.readystate==4)
{
Determines whether the completed prompt code is an OK state
if (xmlhttp.status==200)
{
Pass the returned data as a parameter to the Fill method
Filldata (Xmlhttp.responsetext);
}
}
}
function Filldata (strcity)
{
document.getElementById ("DropDownList1"). options.length=0;
var indexofcity;
VAR City;
The string to be passed by cutting
while (strcity.length>0)
{
Determine if it is the last string
Indexofcity=strcity.indexof (",");
if (indexofcity >0)
{
City=strcity.substring (0,indexofcity);
Strcity=strcity.substring (indexofcity+1);
Fill drop-down box
document.getElementById ("DropDownList1"). Add (New Option (city,city));
}
Else
{
If this is the last string
Lastcity=strcity.substring (0,2);
document.getElementById ("DropDownList1"). Add (New Option (lastcity,lastcity));
Break
}
};
}
</script>

A second page
protected void Page_Load (object sender, EventArgs e)
{
Get the arguments passed over
String City =request.querystring[' city ';
Response.Clear ();
Judging the city name
Switch (city)
{
Case "Beijing":
Fill in related areas
Response.Write ("Chaoyang, Haidian, Dongcheng, Xicheng");
Break
Case "Shanghai":
Response.Write ("Pudong, Jingan, Hongkou, Xuhui");
Break
Case "Jinan":
Response.Write ("Lixia, Licheng, City, overpass");
Break
}
}



-------------------------------------------------------------------------------using callback techniques for local refreshes
<script type= "Text/javascript" >
function Filldata ()
{
var City=document.getelementbyid ("TextBox1"). Value;

<% =this. Clientscript.getcallbackeventreference (This, "City", "Filldll", null)%>;
}
function Filldll (strcity)
{
document.getElementById ("DropDownList1"). options.length=0;
var indexofcity;
VAR City;
The string to be passed by cutting
while (strcity.length>0)
{
Determine if it is the last string
Indexofcity=strcity.indexof (",");
if (indexofcity >0)
{
City=strcity.substring (0,indexofcity);
Strcity=strcity.substring (indexofcity+1);
Fill drop-down box
document.getElementById ("DropDownList1"). Add (New Option (city,city));
}
Else
{
If this is the last string
document.getElementById ("DropDownList1"). Add (New Option (strcity,strcity));
Break
}
};
}
</script>


private string _data;
public string GetCallbackResult ()
{
Returns the processed data
return _data;
}

public void RaiseCallbackEvent (String eventargument)
{
Determine the parameters passed over
Switch (eventargument)
{
Case "Beijing":
_data = "Chaoyang, Haidian, Dongcheng, Xicheng";
Break
Case "Shanghai":
_data = "Pudong, Jingan, Xuhui, Hongkou";
Break
Case "Jinan":
_data = "Licheng, Lixia, City, overpass";
Break
}
}


-------------------------------------------------------------------------------------iframe for local refresh
<script language= "JavaScript" >
function Search ()
{
var City=document.getelementbyid ("TextBox1"). Value;
if (City! = "")
{
document.getElementById ("Iframe1"). src= "myframe.aspx?city=" +city;
}
}
</script>
<iframe src= "myframe.aspx" style= "Text-align:center" id= "iframe1" width= "100%" height= "100%" frameborder= "0" scrolling= "No"/>

Second page myframe.aspx

<div style= "Text-align:center" >
<asp:dropdownlist id= "DropDownList1" runat= "Server" width= "154px" >
</asp:DropDownList></div>
protected void Page_Load (object sender, EventArgs e)
{
Get the arguments passed over
String city = request.querystring["City"];
Judging the city name
Switch (city)
{
Case "Beijing":
Fill in related areas
DropDownList1.Items.Clear ();
DROPDOWNLIST1.ITEMS.ADD ("Chaoyang");
DROPDOWNLIST1.ITEMS.ADD ("Haidian");
DROPDOWNLIST1.ITEMS.ADD ("Dongcheng");
DROPDOWNLIST1.ITEMS.ADD ("Xicheng");
Break
Case "Shanghai":
DropDownList1.Items.Clear ();
DROPDOWNLIST1.ITEMS.ADD ("Pudong");
DROPDOWNLIST1.ITEMS.ADD ("Jingan");
DROPDOWNLIST1.ITEMS.ADD ("Hongkou");
DROPDOWNLIST1.ITEMS.ADD ("Xuhui");
Break
Case "Jinan":
DropDownList1.Items.Clear ();
DROPDOWNLIST1.ITEMS.ADD ("Lixia");
DROPDOWNLIST1.ITEMS.ADD ("Licheng");
DROPDOWNLIST1.ITEMS.ADD ("In the City");
DROPDOWNLIST1.ITEMS.ADD ("flyover");
Break
}
}


---------------------------------------------------------------------------------using scripting methods for local refreshes
<script type= "Text/javascript" >
function Filldata (strcity)
{
document.getElementById ("DropDownList1"). options.length=0;
var indexofcity;
VAR City;
The string to be passed by cutting
while (strcity.length>0)
{
Determine if it is the last string
Indexofcity=strcity.indexof (",");
if (indexofcity >0)
{
City=strcity.substring (0,indexofcity);
Strcity=strcity.substring (indexofcity+1);
Fill drop-down box
document.getElementById ("DropDownList1"). Add (New Option (city,city));
}
Else
{
If this is the last string
document.getElementById ("DropDownList1"). Add (New Option (strcity,strcity));
Break
}
};
}
</script>



Using System.Text;
protected void Page_Load (object sender, EventArgs e)
{
Creating a String Connection object
StringBuilder myscript = new StringBuilder ();
Using strings to organize a JavaScript scripting method
MyScript. Append ("function seekcity () {\ n");
MyScript. Append ("var City=document.getelementbyid (' TextBox1 ')." VALUE; \ n ");
MyScript. Append ("switch (city) {\ n");
MyScript. Append ("Case ' Beijing ': \ n");
MyScript. Append ("Filldata" + getcitystr ("Beijing") + "'); \ n ");
MyScript. Append ("break; \ n ");
MyScript. Append ("Case ' Shanghai ': \ n");
MyScript. Append ("Filldata" + getcitystr ("Shanghai") + "'); \ n ");
MyScript. Append ("break; \ n ");
MyScript. Append ("Case ' Jinan ': \ n");
MyScript. Append ("Filldata" + getcitystr ("Jinan") + "'); \ n ");
MyScript. Append ("break;} \ n ");
MyScript. Append ("}\n");
Using the Register script method on the page of the client, register the script method written by this string.
Page.ClientScript.RegisterClientScriptBlock (typeof (String), "Seekcity", MyScript. ToString (), true);

}
Returns the city's county string by getting the city name
private string Getcitystr (String incity)
{
String City= "";
Switch (incity)
{
Case "Beijing":
City = "Chaoyang, Haidian, Dongcheng, Xicheng";
Break
Case "Shanghai":
City = "Pudong, Jingan, Xuhui, Hongkou";
Break
Case "Jinan":
City = "Licheng, Lixia, Urban, overpass";
Break
}
Returns a string connection containing counties
return city;
}

Ajax real-time local refresh