In the past, there were many methods to call the backend in JS.

Method 1:

1. Create a button to write the called or processed content to button_click in the background;
2. Write a js function on the front-end with the content document. getElementById ("btn1"). click ();
3. Call js functions on the frontend or backend to stimulate the click event, which is equivalent to accessing the c # function in the background;

Method 2:

1. function declaration is public
Background code (change public to protected)
Public string ss ()
{
Return ("");
}
2. You can call <% = fucntion () %> in html.
Foreground script www.2cto.com
<Script language = javascript>
Var a = "<% = ss () %> ";
Alert ();
</Script>

Method 3:

1. <script language = "javascript">
<! --
Function _ doPostBack (eventTarget, eventArgument)
{
Var theForm = document. Form1; // indicates the form of runat = server.
TheForm. _ EVENTTARGET. value = eventTarget;
TheFrom. _ EVENTARGUMENT. value = eventArgument;
TheForm. submit ();
}
-->
</Script>
<Input id = "Button1" type = "button" name = "Button1" value = "button" onclick = "javascript :__ doPostBack ('button1','') ">

Method 4:

<Script language = "javascript">
Function SubmitKeyClick ()
{
If (event. keyCode = 13)
{
Event. cancelBubble = true;
Event. returnValue = false;
Document. all. FunName. value = "Name of the function you want to call ";
Document. form [0]. submit ();
}
}
</Script>

<INPUT onkeypress = "SubmitKeyClick ()" id = "aaa" type = "text">
<Input type = "hidden" name = "FunName"> <〈! -- Used to store the function you want to call --> --〉

In. CS, there are:
Public Page_OnLoad ()
{
If (! Page. IsPost ())
{
String strFunName = Request. Form ["FunName"]! = Null? Request. Form ["FunName"]: "";
// Determine which function to call based on the value returned
Switch (strFunName)
{
Case "enter ()":
Enter (); // call this function
Break;
Case "Others ":
// Call other functions
Break;
Default:
// Call the default Function
Break;
}
}
}

Public void enter ()
{
//...... For example, calculating a value
}

From computer technology sharing-long minghong-space-blog