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How to Allow Only Numeric Value in HTML Text Input Using jQuery

Topic: JavaScript / jQueryPrev|Next

Answer: Use the RegExp test() Method

If you want to allow your users to enter only numeric value in an HTML text input field, you can create a regular expression and test the input value against it using the test() method.

Let's try out the following example which applies a red outline to the text input box if the value entered is not integer or float, applies green outline otherwise:

<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="utf-8">
<title>jQuery Allow Only Numeric Input in HTML Text Input Field</title>
<style>
    .success{
        outline: 2px solid green;
    }
    .error{
        outline: 2px solid red;
    }
</style>
<script src="https://code.jquery.com/jquery-3.5.1.min.js"></script>
<script>
$(document).ready(function(){
    // Define regular expression
    var regex = /^\d*[.]?\d*$/;
    
    $("#myInput").on("input", function(){
        // Get input value
        var inputVal = $(this).val();
        
        // Test input value against regular expression
        if(regex.test(inputVal)){
            $(this).removeClass("error").addClass("success");
        } else{
            $(this).removeClass("success").addClass("error");
        }
    });
});
</script>
</head>
<body>
    <input type="text" id="myInput">
    <p><strong>Note:</strong> This HTML text input only allow numeric keystrokes and decimal ('.')</p>
</body>
</html>

Note that the input event fires on keyboard input, mouse drag, autofill and even copy-paste. But, it will not fire if you paste the same string or select and retype the same character inside the input.

If you want to allow only numeric characters (0-9) in HTML text input, use the regex /^\d*$/. In the above example if you also want to allow negative values you can use the regex /^-?\d*[.]?\d*$/.


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