// LTrim(string) : Returns a copy of a string without leading spaces.
function ltrim(str)
{
   var whitespace = new String(" \t\n\r");
   var s = new String(str);
   if (whitespace.indexOf(s.charAt(0)) != -1) {
      var j=0, i = s.length;
      while (j < i && whitespace.indexOf(s.charAt(j)) != -1)
         j++;
      s = s.substring(j, i);
   }
   return s;
}

//RTrim(string) : Returns a copy of a string without trailing spaces.
function rtrim(str)
{
   var whitespace = new String(" \t\n\r");
   var s = new String(str);
   if (whitespace.indexOf(s.charAt(s.length-1)) != -1) {
      var i = s.length - 1;       // Get length of string
      while (i >= 0 && whitespace.indexOf(s.charAt(i)) != -1)
         i--;
      s = s.substring(0, i+1);
   }
   return s;
}

// Trim(string) : Returns a copy of a string without leading or trailing spaces
function trim(str) {
   return rtrim(ltrim(str));
}
//**************************************************************************************************

<!-- Member Login Validation -->
function login_validate()
{	

	var f = document.loginForm;
	var emailPattern = /^[a-zA-Z0-9._-]+@[a-zA-Z0-9.-]+\.[a-zA-Z]{2,4}$/; 
		
	if(!emailPattern.test(f.email.value))
		{      
	 	alert("Email address is not valid");
		f.email.focus();
		return false;
		}
		
		if(trim(f.password.value)=="")
		{
		alert("Password can not be blank");
		f.password.focus();
		return false;
		}
	
	else{
		f.submit();
	}
		
	
	
	
}

<!-- Member Login Validation -->


<!-- Member forgot Validation -->
function forgot_validate()
{	

	var f = document.forgotForm;
	var emailPattern = /^[a-zA-Z0-9._-]+@[a-zA-Z0-9.-]+\.[a-zA-Z]{2,4}$/; 
		
	if(!emailPattern.test(f.email.value))
		{      
	 	alert("Email address is not valid");
		f.email.focus();
		return false;
		}
	
	else{
		f.submit();
	}
		
	
	
	
}

<!-- Member forgot Validation -->


<!-- Member register Validation -->
function register_validate()
{	

	var f = document.registerForm;
	var emailPattern = /^[a-zA-Z0-9._-]+@[a-zA-Z0-9.-]+\.[a-zA-Z]{2,4}$/; 
		
	if(trim(f.name.value)=="")
		{
		alert("Name can not be blank");
		f.name.focus();
		return false;
		}	
	
	if(!emailPattern.test(f.email.value))
		{      
	 	alert("Email address is not valid");
		f.email.focus();
		return false;
		}
		
		if(trim(f.password.value)=="")
		{
		alert("Password can not be blank");
		f.password.focus();
		return false;
		}
		
		if(f.password.value!=f.repassword.value)
		{
		alert("Password Mismatch");
		f.repassword.focus();
		return false;
		}
	
	else{
		f.submit();
	}
		
	
	
	
}

<!-- Member register Validation -->



<!-- Member details Validation -->
function details_validate()
{	

	var f = document.detailsForm;
	
		
	if(trim(f.name.value)=="")
		{
		alert("Name can not be blank");
		f.name.focus();
		return false;
		}	
	
		
		if(trim(f.password.value)=="")
		{
		alert("Password can not be blank");
		f.password.focus();
		return false;
		}
		
		if(f.password.value!=f.repassword.value)
		{
		alert("Password Mismatch");
		f.repassword.focus();
		return false;
		}
	
	else{
		f.submit();
	}
		
	
	
	
}

<!-- Member details Validation -->


<!-- Advanced Search Validation -->

function validate()
{	
	var f = document.advancedForm;
	if (f.CatId.selectedIndex == 0) {
    alert("Choose the Book Category");
   	f.CatId.focus();
	return false;
  	}
	if (f.GLevelId.selectedIndex == 0){
    alert("Choose the Level of the Book");
   	f.GLevelId.focus();
	return false;
  	}
	if (f.WriterId.selectedIndex == 0){
    alert("Choose the Level of the Book");
   	f.WriterId.focus();
	return false;
  	}
	

	else{
		f.submit();
	}
	
}

<!-- Advanced Search Validation -->

<!-- Newsletter Validation -->
function newsletter()
{	var f = document.newsletterForm;
	var emailPattern = /^[a-zA-Z0-9._-]+@[a-zA-Z0-9.-]+\.[a-zA-Z]{2,4}$/; 
	
	
		if(!emailPattern.test(f.members_email.value))
		{      
	 	alert("Email address is not valid");
		f.members_email.focus();
		return false;
		}
		
	
		
		else{
		f.submit();
	}
		
	
	
}
<!-- Newsletter Validation -->



<!-- Voting option Validation -->
function checkRadio (frmName, rbGroupName) {
 var radios = document[frmName].elements[rbGroupName];
 for (var i=0; i <radios.length; i++) {
  if (radios[i].checked) {
   return true;
  }
 }
 return false;
}

function valFrm() {
 if (!checkRadio("vote-polls","option_id")){
  alert("You did not select any Option");
 return false;
 }
 else{
 return true;
 }
 
}
<!-- Voting option Validation -->