In this short article I will explain how to restrict user to enter only numbers i.e. numeric value in TextBox using jQuery
<html xmlns="http://www.w3.org/1999/xhtml">
<head>
    <title></title>
    <style type="text/css">
        body
        {
            font-size: 9pt;
            font-family: Arial;
        }
    </style>
</head>
<body>
    Numeric Value: <input type="text" id="text1" class = "numeric" />
    <span class="error" style="color: Red; display: none">* Input digits (0 - 9)</span>
    <script type="text/javascript" src="http://ajax.googleapis.com/ajax/libs/jquery/1.8.3/jquery.min.js"></script>
    <script type="text/javascript">
        var specialKeys = new Array();
        specialKeys.push(8); //Backspace
        $(function () {
            $(".numeric").bind("keypress", function (e) {
                var keyCode = e.which ? e.which : e.keyCode
                var ret = ((keyCode >= 48 && keyCode <= 57) || specialKeys.indexOf(keyCode) != -1);
                $(".error").css("display", ret ? "none" : "inline");
                return ret;
            });
            $(".numeric").bind("paste", function (e) {
                return false;
            });
            $(".numeric").bind("drop", function (e) {
                return false;
            });
        });
    </script>
</body>
</html>
 
Explanation:
In the above HTML Markup I have a TextBox for which we need to restrict the user enter only numeric values.
I have specified class property with value numeric to the TextBox so that we can access it via jQuery selectors.
On the window load event handler I have attached three event handlers to handle onkeypress, ondrop and onpaste events of the TextBox.
On the keypress event handler, first I have determined the ASCII code of the keyboard key and then verified that its ASCII code is within the range 48 to 57. I have also taken care of that the key pressed is not an special key like Backspace or Delete, if yes then that too is excluded
For more details on various Keyboard key ASCII code please visit Keyboard Keys and Key Code Values
On the drop event handler, I have simply written return false so that the dropping functionality on the TextBox is disabled.
On the paste event handler, I have simply written return false so that the pasting functionality on the TextBox is disabled.
Restrict user to enter only numeric value ( numbers ) in TextBox using jQuery
 
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