function textDisappear() {
  if (document.forms[0].elements[0].value == 'Enter your email here')
	document.forms[0].elements[0].value = '';
}
 
function textAppear() {
  if (document.forms[0].elements[0].value == "")
	document.forms[0].elements[0].value = 'Enter your email here';
}
 
	
function echeck(str) {
		var at="@";
		var dot=".";
		var lat=str.indexOf(at);
		var lstr=str.length;
		var ldot=str.indexOf(dot);
		if (str.indexOf(at)==-1){
		   alert("Please enter a valid email");
		   return false;
		}
 
		if (str.indexOf(at)==-1 || str.indexOf(at)==0 || str.indexOf(at)==lstr){
		   alert("Please enter a valid email");
		   return false;
		}
 
		if (str.indexOf(dot)==-1 || str.indexOf(dot)==0 || str.indexOf(dot)==lstr){
		    alert("Please enter a valid email");
		    return false;
		}
 
		 if (str.indexOf(at,(lat+1))!=-1){
		    alert("Please enter a valid email");
		    return false;
		 }
 
		 if (str.substring(lat-1,lat)==dot || str.substring(lat+1,lat+2)==dot){
		    alert("Please enter a valid email");
		    return false;
		 }
 
		 if (str.indexOf(dot,(lat+2))==-1){
		    alert("Please enter a valid email");
		    return false;
		 }
		
		 if (str.indexOf(" ")!=-1){
		    alert("Please enter a valid email");
		    return false;
		 }
 
 		 return true;
}
 
function validateForm(){
  if (document.forms[0].elements[0].value=='') {
  	alert("Please enter a valid email");
	return false;
  }
 
  if (echeck(document.forms[0].elements[0].value)==false) {
	return false;
  }
 
  return true;
}