function addLoadEvent(func) {
  var oldonload = window.onload;
  if (typeof window.onload != 'function') {
    window.onload = func;
  } else {
    window.onload = function() {
      oldonload();
      func();
    }
  }
}
var clearDefault = {
	config : {
		inputField : "signup",
		fieldElement : ""
	},
	checkValue : function(myValue) {
		if (clearDefault.config.fieldElement.value == myValue) {
			clearDefault.config.fieldElement.value = "";
		}
	},
	init : function() {
		clearDefault.config.fieldElement = document.getElementById(clearDefault.config.inputField);
		var theValue = clearDefault.config.fieldElement.value;
		clearDefault.config.fieldElement.onclick = function() {
			clearDefault.checkValue(theValue);
		}
	}
}
addLoadEvent(clearDefault.init);