After upgrading from 2019 to 2025.4.1210.462, I am experiencing a JavaScript error when my ASP.NET Web Forms application is opened from Encompass Desktop (embedded browser). The same pages work in modern browsers (Chrome/Edge), but fail inside Encompass.
Environment
Product: Telerik UI for ASP.NET AJAX
Version: 2025.4.1210.462
.NET Framework: 4.8
App type: ASP.NET Web Forms
IIS: Integrated pipeline
Host path: /MyService/
Controls used: RadScriptManager, RadAjaxManager, RadGrid, RadComboBox, RadAjaxPanel, etc.
Entry page from Encompass: Validation.aspx (standalone page, not using a master page)
Telerik CDN: Disabled
RadScriptManager: EnableScriptCombine="false"
Error
When opening MyService from Encompass Desktop, users see:
An error has occurred in the script on this page.
Line: 1
Char: 173461
Error: Invalid character
Code: 0
URL: /MyService/ScriptResource.axd?d=...
What we found
When inspecting the script response, we see modern JavaScript syntax that appears incompatible with the Encompass embedded browser (IE-like engine), for example:
_renderActiveItemStyle:function(e){
var t=this.get_owner().get_id(),
i=`${t}_ActiveItemStyle`;
...
e=e.replaceAll(";"," !important;");
...
}
It looks like ES6 template literals and replaceAll() are causing a parse error in the embedded browser.
Questions
1) Is Q1 2025 officially unsupported in Internet Explorer/embedded WebBrowser-style hosts such as Encompass Desktop?
2) Is the _renderActiveItemStyle function with template literals expected in Q1 2025 RadGrid scripts?
3) Is there any supported configuration to serve IE-compatible JavaScript while staying on Q1 2025?
e.g. OutputCompression, CDN, RenderMode, legacy script bundle, etc.
4) If not, what is the recommended Telerik version for IE/embedded browser scenarios - is R3 2022 SP1 (2022.3.1109) the last supported release?
Environment
Product: Telerik UI for ASP.NET AJAX
Version: 2025.4.1210.462
.NET Framework: 4.8
App type: ASP.NET Web Forms
IIS: Integrated pipeline
Host path: /MyService/
Controls used: RadScriptManager, RadAjaxManager, RadGrid, RadComboBox, RadAjaxPanel, etc.
Entry page from Encompass: Validation.aspx (standalone page, not using a master page)
Telerik CDN: Disabled
RadScriptManager: EnableScriptCombine="false"
Error
When opening MyService from Encompass Desktop, users see:
An error has occurred in the script on this page.
Line: 1
Char: 173461
Error: Invalid character
Code: 0
URL: /MyService/ScriptResource.axd?d=...
What we found
When inspecting the script response, we see modern JavaScript syntax that appears incompatible with the Encompass embedded browser (IE-like engine), for example:
_renderActiveItemStyle:function(e){
var t=this.get_owner().get_id(),
i=`${t}_ActiveItemStyle`;
...
e=e.replaceAll(";"," !important;");
...
}
It looks like ES6 template literals and replaceAll() are causing a parse error in the embedded browser.
Questions
1) Is Q1 2025 officially unsupported in Internet Explorer/embedded WebBrowser-style hosts such as Encompass Desktop?
2) Is the _renderActiveItemStyle function with template literals expected in Q1 2025 RadGrid scripts?
3) Is there any supported configuration to serve IE-compatible JavaScript while staying on Q1 2025?
e.g. OutputCompression, CDN, RenderMode, legacy script bundle, etc.
4) If not, what is the recommended Telerik version for IE/embedded browser scenarios - is R3 2022 SP1 (2022.3.1109) the last supported release?