JavaScript RegEx到PHP RegEx [重复]

This question already has an answer here:

I have a RegExp for e-mail check on the user side in JavaScript like this:

var uzorak = new RegExp("^[_A-Za-z0-9-]+(\\.[_A-Za-z0-9-]+)*@[A-Za-z0-9]+(\\.[A-Za-z0-9]+)*(\\.[A-Za-z]{2,})$");

and i would like to rename it to PHP RegExp for the server side check.

</div>

$("#Save").click(function(){
var uzorak = new RegExp("^[_A-Za-z0-9-]+(\\.[_A-Za-z0-9-]+)*@[A-Za-z0-9]+(\\.[A-Za-z0-9]+)*(\\.[A-Za-z]{2,})$");

var EmailAddress = $("#txt1").val();
var uzorak = new RegExp("^[_A-Za-z0-9-]+(\\.[_A-Za-z0-9-]+)*@[A-Za-z0-9]+(\\.[A-Za-z0-9]+)*(\\.[A-Za-z]{2,})$");

if(!uzorak.test(EmailAddress))
{
  alert('not a valid e-mail address');
}
});
<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script>

<input type="text" Id="txt1"/>
<button id="Save">Save</button>

</div>