未捕获的ReferenceError：在单击链接时分配中的左侧无效

I have looked for every solution, but I still can't figure this out.

<td align="center">
    <?php if($dt->key_status === 1){ ?>
        <a href="javascript:;" title="Return Key" onClick="index.php?mod=form&act=abkrk&vid=<?=$dt->vehicle_id?>"><img src="images/icons/returnkey.png" alt="Return Key" width="16" height="16" border="0" /></a>
    <?php }else{ ?>        
        <a href="javascript:;" title="Get Key" onClick="index.php?mod=form&act=abkgk&vid=<?=$dt->vehicle_id?>"><img src="images/icons/getkey.png" alt="Get Key" width="16" height="16" border="0" /></a>
    <?php } ?>
 </td>

When I clicked the image, I keep getting this error:

index.php?view=tr&sm=abk:321 Uncaught ReferenceError: Invalid left-hand side in assignment

You can't add the link in the onClick attribute like that.

• The href attribute is for the link.
• href="javascript:;" means "do nothing".
• Anything in the onClick attribute will be triggered as javascript.

It should work if you change:

<a href="javascript:;" title="Return Key" onClick="index.php?mod=form&act=abkrk&vid=<?=$dt->vehicle_id?>"><img src="images/icons/returnkey.png" alt="Return Key" width="16" height="16" border="0" /></a>

to

<a title="Return Key" href="index.php?mod=form&act=abkrk&vid=<?=$dt->vehicle_id?>"><img src="images/icons/returnkey.png" alt="Return Key" width="16" height="16" border="0" /></a>