Default value for Wiki Style Renderer Description field (System field)

[Joe]

What I did was, I went to the respective Field Configuration of the project, and edited the description of the Description field

Following is the code I wrote:

<script type="text/javascript">
if (document.getElementById("description").value == "") {
document.getElementById("description").value = "Default Value for Description";}
</script>

But the problem is that, now I see the default value for the Description field ONLY when I'm on the Text mode not the Visual mode and I want to figure out how to see the default value when I'm on the Visual mode