将功能结果添加到我的html电子邮件php

I'm sure this is really simple but its driving me nuts!

<p>'.printHistory($result).' </p>

Above is a snippet of code from my html e-mail,and this is the function printHistory:

function printHistory($result){
    $hisNum=0;
    foreach ($result as $item){
        "<b><u>update Number </u></b>".$hisNum."<br/>";
        "<b>Time: </b>". $item['start_time']."<br/>";
        "<b>Date: </b>". $item['date']."<br/>";
        "<b>Comment: </b>". $item['comment']."<br/>";
        $hisNum=$hisNum+1;
    }
}

I receive no errors, but the text isn't printed to my e-mail. Any help would be appreciated!

you forget to return the string, so no output is produced.

function printHistory($result){
    $hisNum=0;
    $string = "";
    foreach ($result as $item){
       $string .= "<b><u>update Number </u></b>".$hisNum."<br/>";
       $string .= "<b>Time: </b>". $item['start_time']."<br/>";
       $string .= "<b>Date: </b>". $item['date']."<br/>";
       $string .= "<b>Comment: </b>". $item['comment']."<br/>";
       $hisNum=$hisNum+1;
    }
    return $string;
}

You need to echo out the result:

function printHistory($result){
        $hisNum=0;
        foreach ($result as $item){
          echo "<b><u>update Number </u></b>".$hisNum."<br/>" 
              . "<b>Time: </b>". $item['start_time']."<br/>"
              . "<b>Date: </b>". $item['date']."<br/>"
              . "<b>Comment: </b>". $item['comment']."<br/>";
          $hisNum=$hisNum+1;
        }
}