function chkData(f){

		if(f.txtName.value=="")
		{
			alert("Please enter your name.");
			f.txtName.focus();
			return false;
		}
		if(f.txtOrganization.value=="")
		{
			alert("Please enter organization name.");
			f.txtOrganization.focus();
			return false;
		}
		var ph_check=pcheck(f.txtPhone.value);
		if(ph_check!=true)
		{
		alert("Invalid Phone number.");
		f.txtPhone.focus();
		return false;
		}
		var em_check=echeck(f.txtEmail.value);
			if(em_check!=true )  {
			alert(em_check);
			f.txtEmail.focus();
			return false;
		}
		if(f.txtComments.value==""){
			alert("Please enter your comments / questions.");
			f.txtComments.focus();
			return false;
		}
	}
	
 function echeck(str) {
// check the validity of email
		var at="@";
		var dot=".";
		var lat=str.indexOf(at)
		var lstr=str.length
		var ldot=str.indexOf(dot)

		if (str.indexOf(at)==-1 || str.indexOf(at)==0 || str.indexOf(at)==lstr-1){
		   return("Invalid E-mail ID")
		}

		if (str.indexOf(dot)==-1 || str.indexOf(dot)==0 || str.indexOf(dot)==lstr-1){
		    return("Invalid E-mail ID")
		 }

		 if (str.indexOf(at,(lat+1))!=-1){
		    return ("Invalid E-mail ID")
		  }

		 if (str.substring(lat-1,lat)==dot || str.substring(lat+1,lat+2)==dot){
		    return ("Invalid E-mail ID")
		     }

		 if (str.indexOf(dot,(lat+2))==-1){
		    return ("Invalid E-mail ID")
		   }
		
		 if (str.indexOf(" ")!=-1){
		    return ("Invalid E-mail ID")
		    }
	 return true					
}

//Checking the validity of phone
function pcheck(str)
{
	var ValidChars = "0123456789";
	var IsNumber=true;
	var Char;
	if(str.length>=10 && str.length<=11) 
	{
   		for (i = 0; i < str.length && IsNumber == true; i++) 
    	{ 
    	Char = str.charAt(i); 
      		if (ValidChars.indexOf(Char) == -1) 
        	{
        	IsNumber = false;
        	}
      	}
	}
	else
	{
	IsNumber = false;
	}
return IsNumber;
}