JAVASCRIPT

js key is pressed

// You can use window.addEventListener or document.addEventListener
window.addEventListener("keydown", function(event) {
    if (event.key == "key Name"){
        // Do Stuff
    }
});

js when key is pressed

document.addEventListener("keypress", function(event) {
	// do stuff
});

how to detect which key is pressed in javascript

$(this).keypress((e) => {
  if (e.key === "a") alert("you pressed a");
  else alert("you pressed " + e.key);
});

how to get which key is pressed in javascript

function myKeyPress(e){
  var keynum;

  if(window.event) { // IE                  
    keynum = e.keyCode;
  } else if(e.which){ // Netscape/Firefox/Opera                 
    keynum = e.which;
  }

  alert(String.fromCharCode(keynum));
}