mobile number validation in javascript

JavaScript
function telephoneCheck(str) {
  var regex = /^(1\s?)?(\(\d{3}\)|\d{3})[\s\-]?\d{3}[\s\-]?\d{4}$/;
  return regex.test(str);
}<!DOCTYPE html>
<html>
<head>
	<title></title>
</head>
<body>
<form method="post" action="">
	Email:<input type="text"  id="number" onkeyup="validation()">
	</form>
</body>
<script type="text/javascript">
	function validation(){
	var number=document.getElementById("number").value;///get id with value 
	var numberpattern=/^\+?([0-9]{2})\)?[-. ]?([0-9]{4})[-. ]?([0-9]{4})$/;////Regular expression
	if(numberpattern.test(number))
	   {
		document.getElementById("number").style.backgroundColor='yellow';
       }
    else
      {
    	document.getElementById("number").style.backgroundColor='red'; 
      }
	}

</script>
</html>/^\d{10}$/
Source