PHP：POST数据上的mysqli_real_escape_string - 添加反斜杠？

I have a regular input field with type text and a submit button (update_form) in a form. Once the submit button is clicked, the data from the input is sent to a php script that should save it to the DB and display the updated HTML page. All works fine but one thing - I am not quite sure when to use mysqli_real_escape_string.

Example:

if(isset($_POST["update_form"])) {
    connectDatabase(); //just opens the connection

    $name = $_POST["page_name"];

    echo $name . "<br>";
    $name = mysqli_real_escape_string($connection, $name);
    echo $name . "<br>";
    //...do the rest, queryDatabase($query);
}

Let's assume I will type "Tim's place" into the text field and I will hit the submit button. If I use the script above, it will echo the following:

Tim\'s place
Tim\\\'s place

So in the HTML output it will look like this:

Tim's place
Tim\'s place

What does this mean? Why after doing mysqli_real_escape_string I have an additional backslash? Or is this not necessary when using POST variables? Really confused.