Wednesday, October 1, 2014

jQuery Validation – Show & Focus on first error only!

Have you ever wanted to show one error message at a time, or create a different type of visual queue for a specific invalid element on a form? Using the validate options, you can easily create any effect you want.
The example below, is designed to show the first error message in a form and to set focus on that first element. The message is displayed in a basic JavaScript alert box, not very elegant but it makes for a simple demo.
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
<head>
    <title>Show JS Alert - First Validation Error</title>
    <script src="Scripts/jquery-1.4.2.js" type="text/javascript"></script>
    <script src="Scripts/jquery.validate.js" type="text/javascript"></script>
    <script type="text/javascript">
        $(document).ready(function() {
            $("#elForm").validate({
                onfocusout: false,
                invalidHandler: function(form, validator) {
                    var errors = validator.numberOfInvalids();
                    if (errors) {
                        alert(validator.errorList[0].message);
                        validator.errorList[0].element.focus();
                    }
                },
                rules: {
                    TextBox1: { required: true, minlength: 2 },
                    TextBox2: { required: true, minlength: 2 },
                    TextBox3: { required: true, minlength: 2 }
                },
                messages: {
                    TextBox1: { required: "TextBox1 Required", minlength: "TextBox1 MinLength" },
                    TextBox2: { required: "TextBox2 Required", minlength: "TextBox2 MinLength" },
                    TextBox3: { required: "TextBox3 Required", minlength: "TextBox3 MinLength" }
                },
                errorPlacement: function(error, element) {
                    // Override error placement to not show error messages beside elements //
                }
            });
        });
    </script>
 
    <style type="text/css">
        label { width: 90px; display: block; float: left; }
        ul { list-style: none; }
        ul li { line-height: 1.8; }
    </style>
</head>
<body>
    <form id="elForm" action="#">
    <div>
        <h1>jQuery Validation - Show First Error Only</h1>
        <ul>
            <li><label>Text Box 1</label><input type="text" name="TextBox1" id="TextBox1" value="" /></li>
            <li><label>Text Box 2</label><input type="text" name="TextBox2" id="TextBox2" value="" /></li>
            <li><label>Text Box 3</label><input type="text" name="TextBox3" id="TextBox3" value="" /></li>
        </ul>
        <input type="submit" id="submit" value="Validate" />
    </div>
    </form>
</body>
</html>
Here are the important parts to focus on.
1. invalidHandler, this option give you access to the current validator and all the errors messages/items via the “validator.errorlist”.
invalidHandler: function(form, validator) {
    var errors = validator.numberOfInvalids();
    if (errors) {
        alert(validator.errorList[0].message);  //Only show first invalid rule message!!!
        validator.errorList[0].element.focus(); //Set Focus
    }
}
2. errorPlacement, this function controls how error messages are displayed. Since we don’t want any error messages displayed by default, we can override the default errorPlacement with a empty method call.
errorPlacement: function(error, element) {
    // Override error placement to not show error messages beside elements //
}
The end result is a alert box showing the first broken rule for the first invalid element on the page. In the example each input has 2 rules (required and minLength), if you enter a single character into the first text box the message will change from “TextBox1 Required” to “TextBox1 MinLength”.
Posted by at

No comments:

Post a Comment

Subscribe to: Post Comments (Atom)