Summary of js call background and background call foreground Methods

Summary of js call background and background call foreground Methods

1. Execute functions in C # code in javaScript Functions:

Method 1: 1. Create a button to write the called or processed content to button#click in the background;
Copy codeThe Code is as follows:
Protected void button#click (object sender, EventArgs e)
{
This. TextBox1.Text = "voodooer ";
}

2. You can call it at the front-end as follows:
Copy codeThe Code is as follows:
<Input type = "button" value = "Method for accessing C #" onclick = 'document. getElementById ("Button1"). click (); '/>

Method 2: 1. function declaration is public or protected
Copy codeThe Code is as follows:
Public string ss ()
{
Return ("voodooer ");
}

2. frontend call Method
Copy codeThe Code is as follows:
<Script language = javascript>
Var a = "<% = ss () %> ";
Alert ();
</Script>

Method 3: 1. <script language = "javascript">
Copy codeThe Code is as follows:
<! --
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 type = "button" value = "button">

Method 4:
Copy codeThe Code is as follows:
<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 type = "text">
<Input type = "hidden"> <〈! -- Used to store the function you want to call --> --〉

In. CS, there are:
Copy codeThe Code is as follows:
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
}

2. How to access the C # variable in JavaScript?

The answer is as follows:

Method 1: 1. Access the <input type = "hidden" runat = "server">

Method 2: 1. For example, public string n is defined in the background; the format of the variable referenced in front-end js is '<% = n %>' or "+ <% = n %> +"

Method 3: 1. You can register a script on the page after assigning values to variables on the server.

"<Script language = 'javascript '> var temp =" + tmp + "</script>"

Tmp is the background variable, and then you can directly access temp in js to obtain the value.

3. How to access existing JavaScript variables in C?

The answer is as follows:

Method 1: 1. the foreground uses static text controls to hide the field and write the js variable value into it;

2. the backend uses request ["id"] to obtain the value;

Method 2: cookie or session can be used

4. How to access JavaScript Functions in C?

The answer is as follows:

C # execute javaScript Functions in the Code:

Method 1: 1. Page. RegisterStartupScript ("ggg", "<script> SetVisible (1); </script> ");

Method 2: Use the Literal class and
Copy codeThe Code is as follows:
Private void Button2_Click (object sender, System. EventArgs e)
{
String str;
Str = "<script language = 'javascript '> ";
Str + = "selectRange ()";
Str + = "</script> ";
// Literal1.Visible = true;
Literal1.Text = str;
}