一切之后，PHP / JS内容交换是否回响“1”？ 找不到来源

Question

I have a basic content swapper using JS and PHP. Everything was working fine until I noticed the script was echoing a number "1" after placing the results of the swap. There was no number one in my html, php includes, or scripts (that I could find.) Where the hell is it coming from and how can I get it to not appear.

JS

function swapContent(cv){
    $("#workwrap").html(loadgif.gif).show();
    var url = "includescripts/swapscript.php";
    $.post(url,{contentVar:cv},function(data){
        $("#workwrap").html(data).show();
    });
}

PHP SCRIPT

<?php
    $contentVar = $_POST['contentVar'];
    if($contentVar == "logo"){
        echo include("../workincludes/contA.php");
    } else if($contentVar == "print"){
        echo include("../workincludes/contB.php");
    } else if($contentVar == "web"){
        echo include("../workincludes/contC.php");
    }
?>

HTML

<div id="content">
<div id="workwrap">
</div></div>

Answer 1

Remove echo before include call, include returns 1 on success