kiểm tra email bang JavaScript

chipid1989 Tue May 10, 2011 10:31 am

Code:: <HTML> <HEAD> <TITLE>check valid email</TITLE> </HEAD> <BODY bgcolor="#E0F8F7"> <script language = "Javascript"> /* This is code to check valid email using java script. */ function emailCheck(str) { var at="@" var dot="." var lat=str.indexOf(at) var lstr=str.length var ldot=str.indexOf(dot) // check if '@' is at the first position or at last position or absent in given email if (str.indexOf(at)==-1 || str.indexOf(at)==0 || str.indexOf(at)==lstr){ alert("Invalid E-mail ID") return false } // check if '.' is at the first position or at last position or absent in given email if (str.indexOf(dot)==-1 || str.indexOf(dot)==0 || str.indexOf(dot)==lstr){ alert("Invalid E-mail ID") return false } // check if '@' is used more than one times in given email if (str.indexOf(at,(lat+1))!=-1){ alert("Invalid E-mail ID") return false } // check for the position of '.' if (str.substring(lat-1,lat)==dot || str.substring(lat+1,lat+2)==dot){ alert("Invalid E-mail ID") return false } // check if '.' is present after two characters from location of '@' if (str.indexOf(dot,(lat+2))==-1){ alert("Invalid E-mail ID") return false } // check for blank spaces in given email if (str.indexOf(" ")!=-1){ alert("Invalid E-mail ID") return false } return true } function ValidateForm(){ var emailID=document.form.txtEmail //check if email is not entered or only spaces are entereds in appropriate textbox if ((emailID.value==null)||(emailID.value=="")){ alert("Please Enter your Email ID") // set cursor to the textbox provided for email entry emailID.focus() return false } if (emailCheck(emailID.value)==false){ emailID.value="" emailID.focus() return false } return true } </script> <form name="form" method="post" onSubmit="return ValidateForm()"> <p>Enter an Email Address <input type="text" name="txtEmail"></p> <p> <input type="submit" name="Submit" value="Submit"></p> </form> </BODY> </HTML>