How To Display Alert Box When No Json Value Is Given

I have displayed the result of a SPARQL query in a HTML page using Json, my question is when a certain value is entered and the query does not display a result it should display a

Solution 1:

You can do this several different ways:

If bindings is a constant of your object, but may sometimes be empty:

if (data.results.bindings.length) {
    //exists
} else {
    alert('goes here');
}

If bindings is not always set in the response from the server:

if (data.results.hasOwnProperty('bindings')) {
   //exists
} else {
    alert('goes here');
}