Disable browser spellcheck and curly red underlines in RadEditor content area

Environment

Product Version	2019.3.917
Product	RadEditor for ASP.NET AJAX

Description

The misspelled words in the editor's content area get automatically highlighted with curly red underlines.

Solution

The curly red underline is a result of the browser spellchecker that can be disabled by using the spellcheck attribute.

We need to set the spellcheck attribute with a false value to the content area of RadEditor:

<telerik:RadEditor runat="server" ID="RadEditor1" OnClientLoad="OnClientLoad"></telerik:RadEditor>
<script>
    function OnClientLoad(sender, args) {
        sender.get_contentArea().setAttribute("spellcheck", "false");
    }
</script>