How To Supply Default Values for Text Fields


How To Supply Default Values for Text Fields? - PHP Script Tips - Processing Web Forms



If you want to provide a default value to a text field in your form, you need to pay attention to following notes:

  • The default value should be provided in the 'VALUE=default_value' attribute in the <INPUT TYPE=TEXT ...> tag.
  • The length of the default value should be less than the max length specified in the "MAXLENGTH=nnn" attribute. If you provide default value longer than the max length, the default value will be truncated when submitted.
  • You should put the default value inside double-quotes as 'VALUE="$default_value"' to protect spaces.
  • You must apply htmlspecialchars() translation function to the default value to protect HTML sensitive characters, like double quotes.

The PHP script below is a modified version of submit_comments.php with a default value in the "comment" field:

  $comment = 'I want to say: "It\'s a good site! :->"';
  $comment = htmlspecialchars($comment);
  print("<html><form action=processing_forms.php method=post>");
  print("<table><tr><td colspan=2>Please enter and submit your"
    ." comments about</td></tr>");
  print("<tr><td>Your Name:</td>"
    ."<td><input type=text name=name></td></tr>\n");
    ."<td><input type=text name=comment value=\"$comment\" size=40>"
  print("<tr><td colspan=2><input type=submit><td></tr></table>\n");

If you view this PHP page, you will a form with default value nicely displayed in the comment field. If you submit the form, you will get something like this:

Number of values: 2
  name = Alan
  comment = I want to say: \"It\'s a good site! :->\"

Notice that special characters are protected with slashes when form is submitted. See the next tip on how to remove slashes.

2007-04-22, 5284👍, 0💬