Dynamic Error Display - php

Question

Please is there a way i can make my error display dynamic for only the fields that have errors display under each textbox.
The I normally use displays only one error for all of the fields when one field is empty...
Thanks
if (isset($_POST['submit'])) {
$a = mysql_real_escape_string($_POST ['a']);
$b = mysql_real_escape_string($_POST ['b']);
$c = mysql_real_escape_string($_POST ['c']);
$d = mysql_real_escape_string($_POST ['d']);
$e = mysql_real_escape_string($_POST ['e']);
if (($a == "") || ($b == "") || ($c == "") || ($d == "") || ($e == "")) {
echo "<div id=\"content\" >" ;
echo "<div class=\"error\" >" ;
echo "empty";
echo "</div>";
echo "</div>";
} else {
$query = "INSERT INTO user (a, b, c, d, e)
VALUES ($a, $b, $c, $d, $e)";
mysql_query($query);
}
}
?>
Enter Texts <br/>
<form action="<?php echo $_SERVER ['PHP_SELF']; ?>" method="post">
A:<input type="text" name="a" ><br/>
B:<input type="text" name="b" ><br/>
C:<input type="text" name="c" ><br/>
D:<input type="text" name="d" ><br/>
E:<input type="text" name="e" ><br/>
<input type="submit" name ="submit" value="Go"/>
</form>
thank you.

Answer 1

Here is an alternative way todo it, checking and building upon an error array as you go, then if the error array is empty do query.
<?php
//Check form was posted
if($_SERVER['REQUEST_METHOD']=='POST'){
//Pre build allowed array
$allowed=array('a','b','c','d','e','submit');
//Pre build errors array
$errors=array('A was not set',
'B was not set',
'C was not set',
'D was not set',
'E was not set');
//Create Blank error array
$error=array();
//Loop through the POST
foreach($_POST as $key=>$value){
//If key is in allowed array
if(in_array($key,$allowed)){
//Check its at good length
if(strlen(trim($value)) >= 1){
//Assign variable variable the key and value + escape
$$key = mysql_real_escape_string(trim($value));
}else{
//Assign key/value null
$$key = null;
//Assign the error from the errors array to the output error array
$error[$key] = $errors[array_search($key,$allowed)];
}
}else{
$error=array('Rouge POST key');
}
}
//If all is good do query
if(empty($error)){
$query = "INSERT INTO user (a, b, c, d, e)
VALUES ($a, $b, $c, $d, $e)";
mysql_query($query);
}
}?>
Enter Texts <br/>
<form action="" method="post">
A:<input type="text" name="a" ><?php echo (isset($error['a'])?$error['a']:null)?><br/>
B:<input type="text" name="b" ><?php echo (isset($error['b'])?$error['b']:null)?><br/>
C:<input type="text" name="c" ><?php echo (isset($error['c'])?$error['c']:null)?><br/>
D:<input type="text" name="d" ><?php echo (isset($error['d'])?$error['d']:null)?><br/>
E:<input type="text" name="e" ><?php echo (isset($error['e'])?$error['e']:null)?><br/>
<input type="submit" name="submit" value="Go"/>
</form>

Answer 2

Instead of showing error at top, attach following piece of code with each field. It will not show error on form load if your form and action code is on same page.
Try something like this:
A:<input type="text" name="a" ><br />
<?php if( isset($_POST['a']) && trim($_POST['a']) == '' ) { echo 'This field is required'; } ?>
B:<input type="text" name="b" ><br/>
<?php if( isset($_POST['b']) && trim($_POST['b']) == '' ) { echo 'This field is required'; } ?>
C:<input type="text" name="c" ><br/>
<?php if( isset($_POST['c']) && trim($_POST['c']) == '' ) { echo 'This field is required'; } ?>
D:<input type="text" name="d" ><br/>
<?php if( isset($_POST['d']) && trim($_POST['d']) == '' ) { echo 'This field is required'; } ?>
E:<input type="text" name="e" ><br/>
<?php if( isset($_POST['a']) && trim($_POST['a']) == '' ) { echo 'This field is required'; } ?>

Answer 3

Instead of checking all variables at once in ($a == "") || ($b == "") || ($c == "") || ($d == "") || ($e == "") check them one at a time and set individual error variables. Use these to display error messages close to your input field.
For example:
if ( $a == "" ) { $errorA = true; }
A:<input type="text" name="a" ><br/>
<?php print ($errorA ? '<span class="error">A is empty.</span><br/>' : ''); ?>
To prevent the form from being submitted, you could rather use following lines:
$error['A'] = $error['B'] = $error['C'] = .... = $error['Z'] = 0;
if ( $a == "" ) { $error['A'] = 1; }
if ( array_sum($error) > 0 ) {
// do not submit!
}
A:<input type="text" name="a" ><br/>
<?php print ($error['A'] ? '<span class="error">A is empty.</span><br/>' : ''); ?>
Or you simply set a broader error variable like this:
$error = false;
if ( $a == "" ) { $errorA = true; $error = true; }
if ( $b == "" ) { $errorB = true; $error = true; }
if ( !$error ) { //submit form
}
A:<input type="text" name="a" ><br/>
<?php print ($errorA ? '<span class="error">A is empty.</span><br/>' : ''); ?>