You can below script from your side. If your application have any global value. you can use the string part that also working well.
Example :
global_value = 100.
<script type=”text/javascript” language=”javascript”>
var global = global_value;
(OR)
var string = “Test”;
if(global.length==’0′){
alert(global+’No Value’);
}
else{
alert(global+’ Value’);
}
</script>
Here how you want you can use. Which condition or just display string length. You can use your own idea.