Create javaScript variable in code behind of asp.net

How do I register a Javascript variable on the server side (backend) and access it on the client side (Javascript file), without a hidden field, Literal, etc.?

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Answers:

Method 1

Method 2

Method 3

Method 4

Answers:

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Method 1

You can use the RegisterClientScriptBlock-Function from the Page’s ClientScriptManager.

Page.ClientScript.RegisterClientScriptBlock(Page.GetType, "initMyClientVariable", "var myClientVariable=null;", True)

EDIT: according to your new informations, that you want to register a client array, use ClientScriptManager’s RegisterArrayDeclaration Method.

VB.Net example:

Dim myArrayValue As String = """1"", ""2"", ""text"""
Page.ClientScript.RegisterArrayDeclaration("myClientArray", myArrayValue)

According to the new information in my comments that you need access to that variable from an external js-file: you should pass the js-array as argument to the function in the js-file. For example:

callFunctionInJsFile(checkBoxes);

Method 2

You can put the following code in .aspx file …

<script type="text/javascript" >
    var date1 = "<%: DateTime.Now %>";
    var date2 = "<%= DateTime.Now %>";
</script>

<%:  %> works under ASP.NET 4

Method 3

You can put a literal in the xml portion of the code and assign that literal some text:

myLiteral.Text = "<script language="javascript">var myVar = 24;</script>";

This makes myVar globally available on the client side once it’s rendered. You can also use the ClientScriptManager object to use Asp.Net to inject scripts and variables.

Method 4

First place an <asp:Literal ID=”Literal1″ runat=”server”></asp:Literal> tag in the <head> of your .aspx file.

Then in the server side code in your .aspx.cs file, do something like Literal1.Text = “<script type=”text/javascript”>var timer = 3600</script>” and you’ve got yout javascript variable called timer.

That’s it. Have fun!

All methods was sourced from stackoverflow.com or stackexchange.com, is licensed under cc by-sa 2.5, cc by-sa 3.0 and cc by-sa 4.0

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