อยากสอบถามเกี่บวกับ javascript 1. อยากสอบถามว่าถ้าเราใช้ javascript:history.back()

<form method="post" action="next.html">
username:<input type="text"  ><br/>
password:<input type="password"><br/>
email:<input type="text"><br/>
<input type="submit" value="register">
</form>

ยืนยันอีกครับ</br>
<a href ="javascript:history.back() ">ย้อนกลับ</a><br/>
<a href="confrim.php">ตกลง</a>

<script>
function refresh(){
	document.getElementById('imgs').src= "imageVerify.php?"+ Math.random();;
}
</script>
<FORM METHOD=POST ACTION="processor.php">
Code: <INPUT TYPE=TEXT id="code"> <IMG  id="imgs" SRC="imageVerify.php"><BR>
<input type="button"  value="refresh"  onclick="refresh()">

<?php

session_start();
$text ="abdefghijkmnpqrtuyABCDEFGHIJKLMNPQRTUYZ123456789";
$im = imagecreatetruecolor(100, 30);
$bg = imagecolorallocate($im, 255, 255, 255);
$textcolor= imagecolorallocate($im, 0, 0, 0);
// Make the background red
imagefilledrectangle($im, 0, 0, 299, 99, $bg);

// Path to our ttf font file
$font_file = 'TYPEWRITERFROMHELL.ttf';

$rand =substr(str_shuffle($text),0,6);
$_SESSION['verify_code'] =$rand;

// Draw the text 'PHP Manual' using font size 13
imagefttext($im, 15, 0,5, 20, $textcolor, $font_file,$rand);
imagefttext($im, 15, 0,6, 21, $textcolor, $font_file,$rand);


// Output image to the browser
header('Content-Type: image/jpg');

imagepng($im);
imagedestroy($im);
exit();
?>