function isEmail(email){var splitted=email.match("^(.+)@(.+)$");if(splitted==null){return false;}if(splitted[1]!=null){var regexp_user=/^\"?[\w-_\.\']*\"?$/;var len=splitted[1].length;var dotPos=0;var chkFlag=true;for(var i=0;i<len;i++){if(splitted[1].substring(i,i+1)=="."){if(chkFlag){dotPos=i;chkFlag=false;}if(dotPos==i-1||dotPos==0||dotPos==len-1)return false;if(!chkFlag)dotPos=i;}}if(splitted[1].match(regexp_user)==null){return false;}}if(splitted[2]!=null){var regexp_domain=/^[\w-\.]*\.[A-Za-z]{2,4}$/;var len=splitted[2].length;var dotPos=0;var chkFlag=true;for(var i=0;i<len;i++){if(splitted[2].substring(i,i+1)=="."){if(chkFlag){dotPos=i;chkFlag=false;}if(dotPos==i-1||dotPos==0||dotPos==len-1)return false;if(!chkFlag)dotPos=i;}}if(splitted[2].match(regexp_domain)==null){var regexp_ip=/^\[\d{1,3}\.\d{1,3}\.\d{1,3}\.\d{1,3}\]$/;if(splitted[2].match(regexp_ip)==null){return false;}}return true;}return false;}
function validateEmail(txtName){var email=txtName.value; if(email.length>0){if(!isEmail(email)){alert("Please enter valid Email ID.");txtName.focus();}}return;}