{"id":1587,"date":"2021-05-10T06:22:13","date_gmt":"2021-05-10T06:22:13","guid":{"rendered":"https:\/\/phptutorial.net\/?page_id=1587"},"modified":"2025-04-07T08:41:17","modified_gmt":"2025-04-07T08:41:17","slug":"php-filter_has_var","status":"publish","type":"page","link":"https:\/\/www.phptutorial.net\/php-tutorial\/php-filter_has_var\/","title":{"rendered":"PHP filter_has_var Function"},"content":{"rendered":"\n<p><strong>Summary<\/strong>: in this tutorial, you&#8217;ll learn about the <code>filter_has_var()<\/code> function and how to use it to check if a variable exists in an input.<\/p>\n\n\n\n<h2 class=\"wp-block-heading\" id='introduction-to-the-filter_has_var-function'>Introduction to the filter_has_var() function <a href=\"#introduction-to-the-filter_has_var-function\" class=\"anchor\" id=\"introduction-to-the-filter_has_var-function\" title=\"Anchor for Introduction to the filter_has_var() function\">#<\/a><\/h2>\n\n\n\n<p>The <code>filter_has_var()<\/code> function checks if a variable of a specific input type exists.  The <code>filter_has_var()<\/code> function is a part of PHP&#8217;s filter extension.<\/p>\n\n\n\n<p>Here&#8217;s the syntax of the <code>filter_has_var()<\/code> function:<\/p>\n\n\n<pre class=\"wp-block-code\" aria-describedby=\"shcb-language-1\" data-shcb-language-name=\"PHP\" data-shcb-language-slug=\"php\"><span><code class=\"hljs language-php\">filter_has_var ( int $input_type , string $var_name ) : bool<\/code><\/span><small class=\"shcb-language\" id=\"shcb-language-1\"><span class=\"shcb-language__label\">Code language:<\/span> <span class=\"shcb-language__name\">PHP<\/span> <span class=\"shcb-language__paren\">(<\/span><span class=\"shcb-language__slug\">php<\/span><span class=\"shcb-language__paren\">)<\/span><\/small><\/pre>\n\n\n<p>The function has the two parameters:<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li><code>$input_type<\/code> is the type of input that you want to check for a variable. The valid input types are <code>INPUT_GET<\/code>, <code>INPUT_POST<\/code>, <code>INPUT_COOKIE<\/code>, <code>INPUT_SERVER<\/code>, or <code>INPUT_ENV<\/code>.<\/li>\n\n\n\n<li><code>$var_name<\/code> is the name of the variable to check.<\/li>\n<\/ul>\n\n\n\n<p>The <code>filter_has_var()<\/code> function returns <code>true<\/code> if the <code>$var_name<\/code> exists in the <code>$input_type<\/code> or <code>false<\/code> otherwise.<\/p>\n\n\n\n<p>The <code>filter_has_var()<\/code> function only checks if a variable exists. It does not validate or sanitize the input. Typically, you&#8217;ll use the <code>filter_has_var()<\/code> function with other functions like <code>filter_input()<\/code> or <code>filter_var()<\/code> to deal with security.<\/p>\n\n\n\n<h2 class=\"wp-block-heading\" id='checking-a-get-variable'>Checking a GET variable <a href=\"#checking-a-get-variable\" class=\"anchor\" id=\"checking-a-get-variable\" title=\"Anchor for Checking a GET variable\">#<\/a><\/h2>\n\n\n\n<p>The following example uses the <code>filter_has_var()<\/code> function to check if the term exists in the INPUT_GET:<\/p>\n\n\n<pre class=\"wp-block-code\" aria-describedby=\"shcb-language-2\" data-shcb-language-name=\"HTML, XML\" data-shcb-language-slug=\"xml\"><span><code class=\"hljs language-xml\"><span class=\"php\"><span class=\"hljs-meta\">&lt;?php<\/span>\n\n<span class=\"hljs-keyword\">if<\/span> (filter_has_var(INPUT_GET, <span class=\"hljs-string\">'term'<\/span>)) {\n    <span class=\"hljs-keyword\">echo<\/span> <span class=\"hljs-string\">\"Term is set in GET: \"<\/span> . $_GET&#91;<span class=\"hljs-string\">'name'<\/span>];\n} <span class=\"hljs-keyword\">else<\/span> {\n    <span class=\"hljs-keyword\">echo<\/span> <span class=\"hljs-string\">\"Term is not set.\"<\/span>;\n}\n<\/span><\/code><\/span><small class=\"shcb-language\" id=\"shcb-language-2\"><span class=\"shcb-language__label\">Code language:<\/span> <span class=\"shcb-language__name\">HTML, XML<\/span> <span class=\"shcb-language__paren\">(<\/span><span class=\"shcb-language__slug\">xml<\/span><span class=\"shcb-language__paren\">)<\/span><\/small><\/pre>\n\n\n<h2 class=\"wp-block-heading\" id='checking-a-post-variable'>Checking a POST variable <a href=\"#checking-a-post-variable\" class=\"anchor\" id=\"checking-a-post-variable\" title=\"Anchor for Checking a POST variable\">#<\/a><\/h2>\n\n\n\n<p>The following example shows how to use the <code>filter_has_var()<\/code> function to check if the email exists in INPUT_POST:<\/p>\n\n\n<pre class=\"wp-block-code\" aria-describedby=\"shcb-language-3\" data-shcb-language-name=\"HTML, XML\" data-shcb-language-slug=\"xml\"><span><code class=\"hljs language-xml\"><span class=\"php\"><span class=\"hljs-meta\">&lt;?php<\/span>\n\n<span class=\"hljs-keyword\">if<\/span> (filter_has_var(INPUT_POST, <span class=\"hljs-string\">'email'<\/span>)) {\n    <span class=\"hljs-keyword\">echo<\/span> <span class=\"hljs-string\">\"Email is set: \"<\/span> . $_POST&#91;<span class=\"hljs-string\">'email'<\/span>];\n} <span class=\"hljs-keyword\">else<\/span> {\n    <span class=\"hljs-keyword\">echo<\/span> <span class=\"hljs-string\">\"Email is not set.\"<\/span>;\n}\n<\/span><\/code><\/span><small class=\"shcb-language\" id=\"shcb-language-3\"><span class=\"shcb-language__label\">Code language:<\/span> <span class=\"shcb-language__name\">HTML, XML<\/span> <span class=\"shcb-language__paren\">(<\/span><span class=\"shcb-language__slug\">xml<\/span><span class=\"shcb-language__paren\">)<\/span><\/small><\/pre>\n\n\n<h2 class=\"wp-block-heading\" id='filter_has_var-vs-isset'>filter_has_var vs. isset <a href=\"#filter_has_var-vs-isset\" class=\"anchor\" id=\"filter_has_var-vs-isset\" title=\"Anchor for filter_has_var vs. isset\">#<\/a><\/h2>\n\n\n\n<p>The <code>isset()<\/code> function returns <code>true<\/code> if a variable is declared and not <code>null<\/code>. For example, the following checks if the <code>name<\/code> variable in the <code>$_POST<\/code> array:<\/p>\n\n\n<pre class=\"wp-block-code\" aria-describedby=\"shcb-language-4\" data-shcb-language-name=\"PHP\" data-shcb-language-slug=\"php\"><span><code class=\"hljs language-php\"><span class=\"hljs-meta\">&lt;?php<\/span>\n\n<span class=\"hljs-keyword\">if<\/span>(<span class=\"hljs-keyword\">isset<\/span>($_POST&#91;<span class=\"hljs-string\">'name'<\/span>])) {\n    <span class=\"hljs-comment\">\/\/ process the name<\/span>\n}<\/code><\/span><small class=\"shcb-language\" id=\"shcb-language-4\"><span class=\"shcb-language__label\">Code language:<\/span> <span class=\"shcb-language__name\">PHP<\/span> <span class=\"shcb-language__paren\">(<\/span><span class=\"shcb-language__slug\">php<\/span><span class=\"shcb-language__paren\">)<\/span><\/small><\/pre>\n\n\n<p>In this example, the <code>isset()<\/code> checks if the <code>$_POST<\/code> variable has a key <code>'name'<\/code> and the <code>$_POST['name']<\/code> is not null. <\/p>\n\n\n\n<p>However, the <code>isset()<\/code> doesn&#8217;t check whether the <code>name<\/code> variable comes from the HTTP request or not. For example:<\/p>\n\n\n<pre class=\"wp-block-code\" aria-describedby=\"shcb-language-5\" data-shcb-language-name=\"PHP\" data-shcb-language-slug=\"php\"><span><code class=\"hljs language-php\"><span class=\"hljs-meta\">&lt;?php<\/span>\n\n$_POST&#91;<span class=\"hljs-string\">'email'<\/span>] = <span class=\"hljs-string\">'example@phptutorial.net'<\/span>;\n\n<span class=\"hljs-keyword\">if<\/span>(<span class=\"hljs-keyword\">isset<\/span>($_POST&#91;<span class=\"hljs-string\">'email'<\/span>])) { <span class=\"hljs-comment\">\/\/ return true<\/span>\n    <span class=\"hljs-comment\">\/\/ ...<\/span>\n}<\/code><\/span><small class=\"shcb-language\" id=\"shcb-language-5\"><span class=\"shcb-language__label\">Code language:<\/span> <span class=\"shcb-language__name\">PHP<\/span> <span class=\"shcb-language__paren\">(<\/span><span class=\"shcb-language__slug\">php<\/span><span class=\"shcb-language__paren\">)<\/span><\/small><\/pre>\n\n\n<p>In this example:<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li>First, manually set the <code>$_POST['email']<\/code> to a value. <\/li>\n\n\n\n<li>Then, use the <code>isset()<\/code> function to check if the <code>email<\/code> variable exists.<\/li>\n<\/ul>\n\n\n\n<p>As a result, the <code>isset()<\/code> function returns <code>true<\/code>. <\/p>\n\n\n\n<p>Unlike the <code>isset()<\/code> function, the <code>filter_has_var()<\/code> function doesn&#8217;t read the contents of the <code>$_POST<\/code> array. It checks the variables in the request&#8217;s body. Therefore, the following example returns <code>false<\/code>:<\/p>\n\n\n<pre class=\"wp-block-code\" aria-describedby=\"shcb-language-6\" data-shcb-language-name=\"PHP\" data-shcb-language-slug=\"php\"><span><code class=\"hljs language-php\"><span class=\"hljs-meta\">&lt;?php<\/span>\n\n$_POST&#91;<span class=\"hljs-string\">'email'<\/span>] = <span class=\"hljs-string\">'example@phptutorial.net'<\/span>;\n\n<span class=\"hljs-keyword\">if<\/span>(filter_has_var(INPUT_POST, <span class=\"hljs-string\">'email'<\/span>)) { <span class=\"hljs-comment\">\/\/ return false<\/span>\n    <span class=\"hljs-comment\">\/\/ ...<\/span>\n}<\/code><\/span><small class=\"shcb-language\" id=\"shcb-language-6\"><span class=\"shcb-language__label\">Code language:<\/span> <span class=\"shcb-language__name\">PHP<\/span> <span class=\"shcb-language__paren\">(<\/span><span class=\"shcb-language__slug\">php<\/span><span class=\"shcb-language__paren\">)<\/span><\/small><\/pre>\n\n\n<h2 class=\"wp-block-heading\" id='summary'>Summary <a href=\"#summary\" class=\"anchor\" id=\"summary\" title=\"Anchor for Summary\">#<\/a><\/h2>\n\n\n\n<ul class=\"wp-block-list\">\n<li>Use the <code>filter_has_var()<\/code> function to check if a variable exists in a specified type, including <code>INPUT_POST<\/code>, <code>INPUT_GET<\/code>, <code>INPUT_COOKIE<\/code>, <code>INPUT_SERVER<\/code>, or <code>INPUT_ENV<\/code>.<\/li>\n<\/ul>\n<div class=\"helpful-block-content\" data-title=\"\">\n\t<header>\n\t\t<div class=\"wth-question\">Did you find this tutorial useful?<\/div>\n\t\t<div class=\"wth-thumbs\">\n\t\t\t<button\n\t\t\t\tdata-post=\"1587\"\n\t\t\t\tdata-post-url=\"https:\/\/www.phptutorial.net\/php-tutorial\/php-filter_has_var\/\"\n\t\t\t\tdata-post-title=\"PHP filter_has_var Function\"\n\t\t\t\tdata-response=\"1\"\n\t\t\t\tclass=\"wth-btn-rounded wth-yes-btn\"\n\t\t\t>\n\t\t\t\t<svg\n\t\t\t\t\txmlns=\"http:\/\/www.w3.org\/2000\/svg\"\n\t\t\t\t\tviewBox=\"0 0 24 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