var regex = /.*(script\b).*>.*<.*(script\b).*/gi;

var scripts = [
"<script> alert(); </script>",
"<<  ScRiPT   >alert(\"XSS\");//<</ ScRiPT  >",
"<script/src=test.js></script>",
"<script src=test.js></script>",
"<div><script> alert(); </script></div>",
"<script+>alert();</script>",
"<script/script>", //valid
"<scripting></scripting>", // valid
"<script/src=test.js/>" // valid
]

var x = document.getElementById('x');

scripts.forEach(function(script) {
  var i = document.createElement('input');
  i.value = script;

  x.appendChild(i);
  x.appendChild(document.createElement('br'));
})

var btn = document.createElement('button');
btn.innerHTML = 'Click Me';
btn.addEventListener('click', function(e) {
  checkInputs();
});

x.appendChild(btn);

function checkInputs() {
  var inputs = document.getElementsByTagName('input');
  if (!inputs) {
    inputs = []
  }

  for(var i = 0; i < inputs.length; i++) {
    var input = inputs[i];
    if(input) {
      var output = input.value.match(regex);
      console.log(output)
    }
  }
}