please help me : security and required fields with php

[Mr.only]

i need help in this form

 

<FORM action="thanx.php" method="post">
<TABLE width="100%" border=0>
  <TBODY>
  <TR>
    <TD align=center><FONT color=#ff0000>* </FONT>title:<BR><INPUT size=40
     name=title><BR></TD>
    </TR>
      </TBODY>
      <TABLE width="100%" border=0>
       <TBODY>
       <TR>
       <TD align=center><FONT color=#ff0000>* </FONT>Url<BR><INPUT size=40
     name=url value=http://><BR><TD></TR></TBODY></TABLE>
      </TD>
    </TR>
     <TABLE width="100%" border=0>
       <TBODY>
       <TR>
       <TD align=center>description<BR>
       <textarea cols="50" rows="4" name="description"></textarea><BR><TD></TR></TBODY></TABLE>
      </TD>
    </TBODY></TABLE>
    <P style="TEXT-ALIGN: center" align=center><INPUT class=submit type=submit value="add" name=send></TD>
</FORM>

 

first :

 

i want make fields required  "at lest Three letters" using php not java ...

 

but i want the user don't leave the form if this fields empty ..

 

and i need the user don't go the add.php if this fields empty

 

like :: please fill the blank fields

 

second :

some time my users post in the in fields ..something like this

 

 

 

<SCRIPT type=text/javascript>
<!--
//-->
</SCRIPT>

 

or something like this

 

 

 <a href=""</a>

 

and some time user write one letter in the field

i don't accept this ..because it makes problems in the results..

so what can i do to fix this and make security for this .

so can anyone help me ..please

[Pikachu2000]

Please post in the correct forum. I'll move this to the correct on for this time.