diff --git a/adminer/include/functions.inc.php b/adminer/include/functions.inc.php
index eb51e595..59060016 100644
--- a/adminer/include/functions.inc.php
+++ b/adminer/include/functions.inc.php
@@ -673,7 +673,7 @@ function input($field, $value, $function) {
 		}
 		$onchange = ($first ? " onchange=\"var f = this.form['function[" . js_escape($name) . "]']; if ($first > f.selectedIndex) f.selectedIndex = $first;\"" : "");
 		$attrs .= $onchange;
-		echo (count($functions) > 1 ? html_select("function[$name]", $functions, !isset($function) || in_array($function, $functions) || isset($functions[$function]) ? $function : "") : nbsp(reset($functions))) . '<td>';
+		echo (count($functions) > 1 ? html_select("function[$name]", $functions, !isset($function) || in_array($function, $functions) || isset($functions[$function]) ? $function : "", "functionChange(this);") : nbsp(reset($functions))) . '<td>';
 		$input = $adminer->editInput($_GET["edit"], $field, $attrs, $value); // usage in call is without a table
 		if ($input != "") {
 			echo $input;
diff --git a/adminer/static/functions.js b/adminer/static/functions.js
index 6cf09ebc..2b9f3726 100644
--- a/adminer/static/functions.js
+++ b/adminer/static/functions.js
@@ -220,6 +220,21 @@ function editingKeydown(event) {
 	return true;
 }
 
+/** Disable maxlength for functions
+* @param HTMLSelectElement
+*/
+function functionChange(select) {
+	var input = select.form[select.name.replace(/^function/, 'fields')];
+	if (selectValue(select)) {
+		if (input.origMaxLength === undefined) {
+			input.origMaxLength = input.maxLength;
+		}
+		input.removeAttribute('maxlength');
+	} else if (input.origMaxLength >= 0) {
+		input.maxLength = input.origMaxLength;
+	}
+}
+
 
 
 /** Create AJAX request