How to count a specific character by java script in mvc?

  @Html.TextBoxFor(model => model.TagKeyWord, new { @class = "text", @style = "width:98%", @id = "seotagkeyword", onkeyup = "counttagkeyword(this);" })

<script type="text/javascript">
function counttagkeyword() {
        debugger;
        var area = document.getElementById("seotagkeyword").value;
        var count = (area.match(/,/g) || []).length;  
            alert(count);
    }
</script>

In C#
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 string character = model.TagKeyWord;
int count = character.Count(x => x == ',');