// JavaScript Document

function validate_Form(){
	var frm = document.form_demo;
	
	if(frm.txtName.value == ''){
		
		alert("Please Enter Your Name");
		frm.txtName.focus();
		return false;
		
	}else if(emailCheck(frm.txtEmail.value) == false){
		
		frm.txtEmail.value = '';
		frm.txtEmail.focus();
		return false;
		
	}else if(frm.txtPhone.value == ''){
		
		alert("Please Enter Your Phone Number");
		frm.txtPhone.focus();
		return false;
		
	}else if(frm.txtAddress.value == ''){
		
		alert("Please Enter Your Address");
		frm.txtAddress.focus();
		return false;
		
	}else{
		return true;	
	}
}

function emailCheck(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("Invalid Email");
			return false;
		}
		if(str.indexOf(at) == -1 || str.indexOf(at) == 0 || str.indexOf(at) == lstr)
		{	
			alert("Invalid Email");
			return false;
		}
		if(str.indexOf(dot) == -1 || str.indexOf(dot) == 0 || str.indexOf(dot) == lstr)
		{	
			alert("Invalid Email");
			return false;
		}
		if(str.indexOf(at,(lat+1))!=-1)
		{
			alert("Invalid Email");
			return false;
		}
		 if (str.substring(lat-1,lat)==dot || str.substring(lat+1,lat+2)==dot){
		    alert("Invalid E-mail ID");
		    return false;
		 }

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