WordPress获取用户

嗨，我正在尝试进行实时搜索，以便在用户注册时搜索现有电子邮件。下面是我的jquery脚本

$("#wjp_register input#user_email").change(function(){
    console.log("lol");
    var email=$("#wjp_register input#user_email").val();
      $.ajax({
            type:"post",
            dataType : 'JSON',
            url:"/wordpress/wp-content/themes/tsf/wpjobboard/job-board/check.php",
            data:"email-address="+email,
                success:function(result){
                if(result==0){
                    console.log(result);
                    $(".error").html(" Username available");
                }
                else{
                    console.log(result);
                    $(".error").html("Username already taken");
                    proceed = false;
                }
            }
         });
});

当我在开发人员控制台中检查响应时，电子邮件已成功回显，但 wordpress get_user_by似乎不起作用。

我的 php 脚本

<?php
$mm = $_POST['email-address'];
if ( isset( $_POST['email-address'] ) && ! empty( $_POST['email-address'] ) ) {
  //sanitize the data
  $email_addr = trim( strip_tags( stripslashes( $_POST['email-address'] ) ) );
  echo $email_addr;//This is printed successfullt
  echo "<br>";
  //This below part doesnt work :(
    if( false == get_user_by( 'email', $email_addr ) ) {
        echo "Doesnt exist";
    } else {
        echo "exists";
    }
}
?>