PHP Form Validation
In this chapter you will learn:
Description
Basic input validation in PHP is done using the following functions.
is_string(),is_numeric(),is_float(),is_array(), andis_object().
Each of these functions take a variable and return true if that variable is of the appropriate type.
The three basic validation checks we should do.
- whether we have required variables,
- whether the variables have a value assigned, and
- whether they have the the type we are expecting.
After the basic check, we can do more check, such as integer value range, the string length, count of array elements, etc.
CTYPE functions
There are eleven CTYPE functions in total.
they work in the same way as is_numeric().
| Function | Meaning |
|---|---|
| ctype_alnum() | Matches A?Z, a?z, 0?9 |
| ctype_alpha() | Matches A?Z, a?z |
| ctype_cntrl() | Matches ASCII control characters |
| ctype_digit() | Matches 0?9 |
| ctype_graph() | Matches values that can be represented graphically |
| ctype_lower() | Matches a?z |
| ctype_print() | Matches visible characters (not whitespace) |
| ctype_punct() | Matches all non-alphanumeric characters (not whitespace) |
| ctype_space() | Matches whitespace (space, tab, new line, etc.) |
| ctype_upper() | Matches A?Z |
| ctype_xdigit() | Matches digits in hexadecimal format |
<?PHP
$var = "123456789a";
print (int)ctype_digit($var);
?>
Example
The following code checks
whether the $Age variable has a numeric value between 18 and 30.
if (isset($Age)) {
if (is_numeric($Age)) {
if (($Age > 18) && ($Age < 30)) {
print " input is valid";
} else {
print "Sorry, you're not the right age!";
}// j a va 2 s. com
} else {
print "Age is incorrect!"
}
} else {
print "Please provide a value for Age.";
}
Next chapter...
What you will learn in the next chapter:
- What is a form file upload field
- Accessing Information on Uploaded Files
- Fields of file information
- Error
- Limiting the Size of File Uploads
- Storing and Using an Uploaded File
- Example - Handling File Uploads
- Example - Move a uploaded file
- Example - Checking Uploaded Files
- Example - File Upload Script and Copy
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