EMail Validation using Regular Expressions

Using Regular Expressions in Java, we can validate where the given email-id string is of the valid format. Here is a sample.

import java.util.regex.Matcher;
import java.util.regex.Pattern;

public static boolean validateEmailId(String astrEmailId) {
  //Set the email pattern string
  Pattern p = Pattern.compile(".+@.+\\.[a-z]+");
  //Match the given string with the pattern
  Matcher m = p.matcher(astrEmailId);
  //check whether match is found
  return m.matches();
}

RegExp can also be used in JavaScriptto validate EMail ID

function isEmail(str) {
  // are regular expressions supported?
  var supported = 0;
  if (window.RegExp) {
    var tempStr = "a";
    var tempReg = new RegExp(tempStr);
    if (tempReg.test(tempStr)) {
      supported = 1;
    }
  }
  if (!supported) {
    return (str.indexOf(".") > 2) && (str.indexOf("@") > 0);
  }
  var r1 = new RegExp("(@.*@)(\\.\\.)(@\\.)(^\\.)");
  var r2 = new RegExp("^.+\\@(\\[?)[a-zA-Z0-9\\-\\.]+\\.
                     ([a-zA-Z]{2,3}[0-9]{1,3})(\\]?)$");
  return (!r1.test(str) && r2.test(str));
}