jquery - Javascript replace with regex not affecting string -

i have webapp task manager.

the app recognises day/month in string.

i have function replicate selected tasks today, trying make function update date in string.

so, example, do task! 29/5 become do task! 1/6.

the function looks this:

var d   = new date(); var mon = d.getmonth()+1; var day = d.getdate();  $('input.replicatecheck:checkbox:checked').each(function(){     //string of row (nam)     var nam = $(this).parent().find('input.row-name').val();      //replace existing date current date     nam = nam.replace('\d{1,2}\/\d{1,2}',day+'/'+mon);      console.log(nam); }); 

however isn't replacing date in string.

the issue line:

nam = nam.replace('\d{1,2}\/\d{1,2}',day+'/'+mon); 

why isn't working?

edit following answers, requested, here working version of i'm trying achieve:

$('button#go').click(function() {    var text = $('#testinput').val();      var d = new date();    var mon = d.getmonth() + 1;    var day = d.getdate();      newtext = text.replace(/\d{1,2}\/\d{1,2}/, day + '/' + mon);      alert(newtext);  });

* {    width: 100%;    box-sizing: border-box;    -moz-box-sizing: border-box;    -webkit-box-sizing: border-box;    padding: 10px;  }  button {    margin-top: 20px;  }

<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script>  <input type="text" id="testinput" value="the quick brown fox jumps on 26/5" />  <br/>  <button id="go">go!</button>

you're missing regex delimiters:

nam = nam.replace(/\d{1,2}\/\d{1,2}/, day+'/'+mon);