jQuery - Phone number validation

HTML

Phone Number:
<input type='text' id='txtPhone' value="+64211426645" />
<span id="spnPhoneStatus"></span>

<br/>
<br/>
<input type="button" value="Submit" id="btnSubmit" />
<br/>
<br/>
<div></div>

CSS

body {
    padding: 10px;
    font-family: Arial;
    Font-size: 10pt;
}
span {
    font-weight:bold;
}

JavaScript

function IsNumeric(e) {
       console.log(e.keyCode);
       var keyCode = e.which ? e.which : e.keyCode
       var ret = ((keyCode >= 48 && keyCode <= 57) || specialKeys.indexOf(keyCode) != -1);
       return ret;
   }
var specialKeys = new Array();
   specialKeys.push(8); //Backspace
   specialKeys.push(43); //plus
   specialKeys.push(40); // (
   specialKeys.push(41); // )
   specialKeys.push(45); // -
   function IsNumeric(e) {
       console.log(e.keyCode);
       var keyCode = e.which ? e.which : e.keyCode
       var ret = ((keyCode >= 48 && keyCode <= 57) || specialKeys.indexOf(keyCode) != -1);
       return ret;
   }
   
   $('#txtPhone').