The HTML DOM Input Password pattern property is used for setting or returning the pattern attribute of an input password field. It checks the password against a regular expression specified by the pattern property.
Syntax
Following is the syntax for
Setting the pattern property −
passwordObject.pattern = regexp
Here, regexp is a regular expression against which the password field is checked.
Example
Let us look at an example for the password pattern property −
<!DOCTYPE html>
<html>
<body>
<h1>Input Password pattern property</h1>
<p>The password can either be of three numeric characters or 6 alphabet characters from a to g</p>
<form action="/Sample_page.php">
Password: <input type="password" id="PASS" name="passW" pattern="[0-9]{3}|[a-g]{6}" title="Three numeric character or 6 alphabet between a-g">
<input type="submit">
</form>
<br>
<button onclick="passPattern()">GET PATTERN</button>
<p id="Sample"></p>
<script>
function passPattern() {
var P = document.getElementById("PASS").pattern;
document.getElementById("Sample").innerHTML ="The pattern attribute value is"+ P;
}
</script>
</body>
</html>Output
This will produce the following output −
On entering password that is not matched by regex specified in the pattern property −
On clicking the GET PATTERN button −
In the above example
We have created an input element with type password id=”Pass”, name=”PassW” and pattern="[0-9]{3}|[a-g]{6}". Here the pattern attribute value is a regex specifying that you could either enter three numeric value or 6 alphabets ranging from a to g. If the input doesn’t match this regex then the title attribute value is displayed over the input box. This password field is inside a form with action attribute value set to “/Sample_page.php”. This is where our form data will be submitted on clicking the submit button −
<form action="/Sample_page.php">
Password: <input type="password" id="PASS" name="passW" pattern="[0-9]{3}|[a-g]{6}" title="Three numeric character or 6 alphabet between a-g">
<input type="submit">
</form>We have then created the GET PATTERN button that will execute the passPattern() method when clicked by the user −
<button onclick="passPattern()">GET PATTERN</button>
The passPattern() uses the getElementById() method to get the input field with type password and get its pattern property which returns a regex of type string.. The regex string is assigned to variable P and displayed in the paragraph with id “Sample” using its innerHTML property.
function passPattern() {
var P = document.getElementById("PASS").pattern;
document.getElementById("Sample").innerHTML ="The pattern attribute value is"+ P;
}