问题：如何使 (null) 不出现在 (document.write) 中

Question: How to do so that (null) does not appear in (document.write)

我如何更改我的代码，以便在用户按下取消时，下面的代码将写入 document.write("#DELETE") 或只是留空 space？

<!DOCTYPE html>
<html>
<body>
<script language="JavaScript">
var a = prompt("Put a text");

if (a === null || !a) {
    document.write("");
} else {
   document.write( "Your Text is: " + a );
}
</script>
</body>
</html>

var radiuuss = prompt("Please set the radius");
document.write("Press 1 to put the code or press 2 to clear section");   
if (radiuuss === null) {
    document.write("#DELETE");
} else {
   // document write a message with the value of the radiuuss.
}