Simple Button

by justinwyllie

HTML

Greet
<input id="name" />

<button id="buttonx">
Press me
</button>

<div id="userName">

</div>

JavaScript

var myButton = document.querySelector("#buttonx");
 myButton.onclick = greetMe;
 
 function greetMe() {
    var myBox = document.querySelector("#name");
    var userNameField = document.querySelector("#userName");
    var user = myBox.value;
    if (user == '') {
    	  alert("Please enter your name");
    } else if (user.length < 4) {
    		alert("More than 4 chars");
    } else {
        userNameField.innerHTML = "Hello " + user;
    }
}