Edit in JSFiddle

$("#form-input").on({
	keydown: function(e) {
  	if (e.which === 32)
    	return false;
  },
  keyup: function(){
  	this.value = this.value.toLowerCase();
  },
  change: function() {
    this.value = this.value.replace(/\s/g, "");
    
  }
});

<input id="form-input" placeholder="Type some text here...">

input {
  border: 3px solid #9E9E9E;
  border-radius: 5px;
  height: 45px;
  width: 450px;
  font-size: 24px;
  color: #212121;
  margin: 25px 0px 0px 25px;
  padding: 15px;
}