这段代码为什么不能输出值?求教大神!
这段代码为什么不能输出materialname里的值?求教大神!
<FORM method="post" action="" target=_blank><TABLE border=0 cellSpacing=0 cellPadding=0 width=200><TBODY><TR><TD id=term_search_l></TD><TD class=term_search_m o> <p> <INPUT type="text" value="请输入材料名称" name="materialname" style="font-family:'微软雅黑' '宋体';" onfocus="if (value==defaultValue) value=''; " onblur="if(!value) {value=defaultValue}"> </p></TD></TR> </TBODY></TABLE></FORM><div id="button1"><input type="submit" name="submit" id="button" value="" style="color:#FFF; font-family:"微软雅黑"; font-size:24px"; onmousedown="this.blur();this.style.backgroundPosition='left -29px'" onmouseup="this.blur();this.style.backgroundPosition='left top'"/></div><p><?phpif($_POST[submit]==""){ echo $_POST[materialname]; }?></p></div>