StrPos总是返回False？

Question

I've been working on a very basic search engine. It basically operates by checking if the word exists. If it does, it returns the link. I know most of you would suggest to create a database from phpMyAdmin but I don't remember the password to make the mySql_Connect command work.

Anyway here is the code:

<?php

session_start();

$searchInput = $_POST['search'];

var_dump($inputPage1);
var_dump($searchİnput);

$inputPage1 = $_SESSION['pOneText'];
$inputPage2 = isset($_SESSION['pTwoText']) ? $_SESSION['pTwoText'] : "";
$inputPage3 = isset($_SESSION['pThreeText']) ? $_SESSION['pThreeText'] : "";

if (strpos($inputPage1, $searchInput)) {
    echo "True";
} else {
    echo "False";
}

?>

When I search a word, any word from any page, weather it exists or not, it always returns false. Does anyone know why?

Answer 1

From the PHP documentation:

Warning: This function may return Boolean FALSE, but may also return a non-Boolean value which evaluates to FALSE. Please read the section on Booleans for more information. Use the === operator for testing the return value of this function.

So the function returns the integer 0 since $searchInput starts at the first character of $inputPage1. Since it is inside an if condition, that expects a boolean, the integer is then converted to one. When converted to boolean, zero is equal to false so instead the else block is executed.

To fix it, you need to use the !== operator (the not equal equivalent of ===):

if (strpos($inputPage1, $searchInput) !== false) {
    //...