strange string handling

this is for me quite strange, what is happening; I have a sentence which gets corrupted when using a string variable, while work when using a fixed string (the fck part), and totally messes up when string variable (there are instances where " ' " are used while these are very compacted in the shown ) ------- in my php echo "<A href=head_show.html?Disp_head=" . urlencode($nxt_head_name) .. "&Row_no=" .$row_no. ">" ; //echo "<img src='" . $img_sub_dir . $disp_head_name . "'" . " align='left' > </img> </A> "; echo "<img src='" . $img_sub_dir . "fck". "'" . " align='left' > </img> </A> "; ----- the generated text as shown by browser in the first case, when running the // - away commented above, having seconnd awaycommented instead <a href="head_show.html?Disp_head=gaffer1.jpg&Row_no=1"> <img align="left" heads3c.jpg''="" src="/WEP/heads/"></img> </a>