on enter press javascript in input code example

Example 1: how to check if enter is pressed javascript

$('#usersearch').keydown(function(e){
    if(e.keyCode === 13){
            alert("Enter was pressed ");
     }  
});

Example 2: javascript submit form when enter key pressed

//submit form when 'Enter' key is pressed while in myInputID
document.getElementById("myInputID").addEventListener("keyup", function(event) {
    if (event.keyCode === 13) {
    	document.getElementById("myFormID").submit();
		return false;
    }
});