In asp.net JS, CS calls multiple methods for the value of backend variables

(1) // backend: Publicstringstr = "123"; // Public type is recommended.

Write the following code directly in the HTML code of the AspX front-end page:

<Td> <% = str %> </td>

 

(2) use JS to obtain the server-side control value on this page:

Server-side control value:

The code is as follows:

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Functiona ()      { Vari; I = document. getElementById ('<% = Server Control id. ClientID %>'). value; // Obtain the Label control value Document. getElementById ('<% = lblUserName. ClientID %>'). innerText = I;      } (3) use JS to retrieve   Function B () { // The id of the. ascx user control on this page, that is, the ID name in the <uc> label, and the server control ID in the. ascx page // Connect "_" Var j = document. getElementById ('<% = uc id. ClientID %>' + "_ txtID"). value; // TextBox // Use the following method when getting the value of the Label control. Some friends may also use the method above, so they cannot get it ...... Var jj = document. getElementById ('<% = uc id. ClientID %>' + "_ txtID") .. innerHTML; // Label }

 
Add:
If JavaScript is called in a server control, you cannot bind the background variable directly. You must declare the js variable and assign the value to the background variable first.

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<Script> Var testTxt = "<% = stetValue %> "; </Script> <Div> <Input type = "button" onclick = "return confirm ('<% = stetValue %>')" value = "test"/> // client controls can be directly used <Asp: Button ID = "Button1" runat = "server" Text = "test" OnClientClick = "return confirm (testTxt)"/> </Div>

 

In addition:

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;
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)

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Public string ss () { Return (""); }

2. You can call <% = fucntion () %> in html.
Foreground script

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<Script language = javascript> Var a = "<% = ss () %> "; Alert (); </Script>

Method 3: 1

The code is as follows:

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, <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:

The code is as follows:

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<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:

The code is as follows:

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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 }

Question 2. How to access the C # variable in JavaScript?
The answer is as follows:
Method 1: 1. Access <input id = "xx" 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

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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;

}