How to Invoke JS function in IFrame from code behind - javascript

Asp.Net 4.5 (WebForm)
How can I invoke a js function in Iframe from code behind successfully?
I am using RegisterClientScriptBlock to fire JS function in aspx page that in turn invokes the JS function in html page of iframe.
The Client Button in main page works fine.
The Server Button does not work as intended. However it does recognize the iframe object and contentWindow.
Error
TypeError: Object doesn't support property or method 'TestFunc'
Any constructive help would be appreciated. Note: this is a stripped down example for clarity.
MainPage.aspx
<head runat="server">
<title></title>
<script type="text/javascript">
function InvokeJS(param) {
var iframe = document.getElementById("MyIFrame");
try {
iframe.contentWindow.TestFunc(param);
//=============================================================
//Would really like to use the .apply method over calling the
//function directly. This does work in pure HTML, but not aspx
//=============================================================
//var _ARGS = [];
//_ARGS.push(param);
//iframe.contentWindow('TestFunc').apply(null, _ARGS);
} catch (e) {
alert(e);
}
}
</script>
</head>
<body>
<form id="form1" runat="server">
<asp:ScriptManager ID="ScriptManager1" runat="server"></asp:ScriptManager>
<asp:UpdatePanel ID="UpdatePanel1" runat="server">
<ContentTemplate>
<asp:Button ID="ServerButton" runat="server" Text="Server" />
<input id="ClientButton" type="button" value="Client" onclick="InvokeJS('From Client');" />
<br />
<br />
<iframe id="MyIFrame" runat="server" src="Pages/Test.html" style="width: 700px; height: 300px;"></iframe>
</div>
</ContentTemplate>
</asp:UpdatePanel>
</form>
</body>
MainPage.aspx (CodeBehind)
Protected Sub ServerButton_Click(sender As Object, e As EventArgs) Handles ServerButton.Click
ScriptManager.RegisterClientScriptBlock(Me, Me.GetType, "InvokeJS", "InvokeJS('From Server');", True)
End Sub
Test.html (loads into iframe)
<head>
<title>Test</title>
<script type="text/javascript">
function TestFunc(param) {
document.getElementById("DisplayParam").innerHTML = param;
}
</script>
</head>
<body>
<h1>HTML Page</h1>
<h2 id="DisplayParam"></h2>
</body>
</html>

window.onload = TestFunc(); doesn't work because Test.html actually didn't fully loaded before the onload event raised, it's same with ServerButton, because the scriptblock was registered before the test.html loaded. that's why no TestFunc is not available to call.
You can try
<asp:Button ID="ServerButton" runat="server" Text="Server" OnClientClick="InvokeJS('From Server');" />
I don't think you like it if you want it to do something before run the script
Then play this trick
<script type="text/javascript">
//this is help check if postback by Server Button, if yes then invoke
var prm = Sys.WebForms.PageRequestManager.getInstance();
prm.add_beginRequest(BeginRequestHandler);
function BeginRequestHandler(sender, args) {
if (args._postBackElement.id == '<%=ServerButton.ClientID%>')
$('#MyIFrame').load(function(){
InvokeJS('From Client');
console.log('load the iframe');
});
}
</script>

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<html xmlns="http://www.w3.org/1999/xhtml">
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more specifically this is the function im trying to run
<script type="text/javascript">
const add = (param) => {
alert("hi");
$("div.auto-style1").append("<p>'" + param + "'</p>");
}
</script>
im trying to call this function from the C# code behind the page like this
protected void Button1_Click(object sender, EventArgs e)
{
String p = "this is a message";
ScriptManager.RegisterClientScriptBlock(this, GetType(), "myfunction", "add('" + p + "');", true);
}
If I try to run a JS function that produces a console log or an alert on the page it works fine. Maybe it is related to the Postback property in the ASP button?
If anyone can shed some light on this I will be thankful.
There is no any .auto-style1 class in your code. Please add a class in div to work this code.
<form id="form1" runat="server">
<div class="auto-style1">
</div>
<asp:Button ID="Button1" runat="server" OnClick="Button1_Click" style="height: 26px" Text="Button" />
<asp:DropDownList ID="DropDownList1" runat="server" OnSelectedIndexChanged="DropDownList1_SelectedIndexChanged">
</asp:DropDownList>
<div class="container">
some text
</div>
</form>

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{
if (!Page.IsPostBack)
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This is where the error is called. The page reloads and the error is shown.
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-------------------------
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}
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<body>
<button onclick="showHideAlert();">Show/Hide alert</button>
<div class="alert">ALERT!!!</div>
</body>
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<html>
<head>
<script>
function onError() {
try {
...
} catch (...) {
var error
error = "button was pressed"
alert(error)
}
}
</script>
</head>
<body>
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</html>
<html>
<head runat="server">
<title></title>
<meta http-equiv="X-UA-Compatible" content="IE=edge;" /><%-- Also Check Compatible View --%>
<%-- Put all your jQuery... Here I'm showing an example--%>
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</head>
<body>
<script type="text/javascript" language="javascript">
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window.setTimeout(function() {
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$(this).remove();
});
}, 3000);
});
</script>
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<asp:TextBox ID="txt" runat="server"></asp:TextBox>
<div runat="server" visible="false" id="AlertDanger" class="alert alert-danger">
× <strong>You must have at
least one employee to process</strong>
</div>
</form>
</body>
</html>
Note:- I think you have missed this... put your jQuery code inside your body tag...

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I refer following blog also:
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Thank you.
There should be a file called jquery-1.3.2.js and/or jquery-1.3.2.min.js.
You need to reference one of those two. The VSdoc file you are using is just for intellisense purposes in older versions of Visual Studio.
Your Script tag should look like this:
<script type="text/javascript" src="scripts/jquery-1.3.2.js"></script>
In addition you might want to update to a newer verison of JQuery. According to Jquery.com/download, the uptodate-versions are 1.11.3 and 2.1.4.
Inside visual Studio you can also use the package manager console to install a new version of Jquery using the following command(s):
Install-Package jQuery
Update-Package jQuery

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<html xmlns="http://www.w3.org/1999/xhtml" >
<head runat="server">
<title>Untitled Page</title>
</head>
<body>
<form id="form1" runat="server">
<div>
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</body>
</html>
When I click the button I receive the error message 'aaa' is undefined
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Your <script> should be inside your <head> section, or at least before the part where you call aaa().
Right now, you're defining aaa() AFTER it has initialized your button.

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Design page containing Update panel
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