jQuery addClass example

Change class name on click in jQuery

HTML

<div id="banner-message">
  <div id="output"></div>
  <button>Run the Master Control Program</button>
</div>

CSS

body {
  background: #20262E;
  padding: 20px;
  font-family: "Courier New", monospace;
}

#banner-message {
  background: #888;
  border-radius: 4px;
  padding: 20px;
  font-size: 25px;
  text-align: center;
  transition: all 0.2s;
  margin: 0 auto;
  width: 300px;
}

button {
  background: #444;
  border: none;
  border-radius: 5px;
  padding: 8px 14px;
  font-size: 15px;
  color: #fff;
}

#banner-message.alt {
  background: #040;
  color: #0f0;
  margin-top: 40px;
  width: 90%;
  border:2px solid #020;
}

#banner-message.alt button {
  background: #fff;
  color: #000;
}

#output { font-size:0.6em; text-align:left }

JavaScript

// output display
var banner = $("#banner-message")
var button = $("button")
var mcptitle = $("mcptitle")
button.on("click", function(){

	if (typeof MCPOutput == 'undefined')
  { MCPOutput = "Error: MCPOutput is not defined. MCP code must be copied from the ruleset into the Javascript window."; }
	banner.addClass("alt")
  button.css({ display: "none" });
	document.getElementById("output").innerHTML = MCPOutput;
})