CODEWITHSUNDEEP
javascriptc#asp.net
Gil Epshtain
Gil Epshtain

Reputation: 9811

How to pass parameters from Aspx to Javascript

My question is quite simple, I have a website developed in Asp.Net. I wan't to pass a parameter from server (aspx file) to client (javascript file).

Lets say I have a asp:Button, and when OnClientClick event fires I want to call javascript function with parameter from the server.

Let simplify the example, and lets say this is my webpage:

<html xmlns="http://www.w3.org/1999/xhtml">
<body>
    <form id="form" runat="server">

        <div runat="server" id="divID" >div text here...</div>
        <br />

        <asp:Button runat="server" text="click1"
            OnClientClick='<%= "alert("  + this.divID.ClientID + "); return false;" %>'
            />

        <asp:Button runat="server" text="click2"
            OnClientClick="alert('<%= this.divID.ClientID %>'); return false;"
            />

    </form>
</body>
</html>

The first button throw an client side error.
The 2nd button alert the string "<%= this.divID.ClientID %>" and not the actual value.

What I'm missing??

Upvotes: 0

Views: 2321

Answers (3)

Gil Epshtain
Gil Epshtain

Reputation: 9811

OK, so I found a solution, first of all the problem is that not all attribute support server side tags (<%= %> or <%# %>). And the attribute OnClientClick don't support them. However there is a work around.

  1. Add the Button\ImageButton an ID and run on it DataBind() on the server side.
  2. Use data binding tags <%# %>

The solution will be:

aspx code:

<div runat="server" id="divID" >div text here...</div>

<asp:Button ID="btn1" runat="server" text="click1"
 OnClientClick='<%# "alert("  + this.divID.ClientID + "); return false;" %> '/>

cs code:

protected void Page_Load(object sender, EventArgs e)
{
    btn1.DataBind();
}

now after running DataBind() on this element it's possible to use server side data binding tags to pass parameters

Upvotes: 0

Ryan
Ryan

Reputation: 97

One could always set a hidden form field with the value on the server side. You can then just reference that hidden field in the javascript. I find it easier to do it that way than to mess with the funkiness that is ASP.net

Upvotes: 0

Tim
Tim

Reputation: 4099

Generate your ClientClick code in server-side code.

(BTW - you don't have IDs on your buttons...)

In Page_Load, you could put:

btn1.OnClientClick="alert('"  + this.divID.ClientID + "'); return false;";

Upvotes: 0

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