Important Validation using JQuery

This code snippet is for Important Validation using JQuery.

1. Phone number validation using jquery,

<html>

<head>
    //Import jquery.Min.js
    <script type="text/javascript">
        $.fn.isPhoneNumber = function(options) {
            intRegex = /^[0-9]{1,10}$/;
            phoneNumber = this.val();
            if ((phoneNumber.length != 10) || (!intRegex.test(phoneNumber))) {
                this.val("");
                this.attr("placeholder", "Invalid Phone Number");
                return false;
            }
            return true;
        };

        function validate() {
            $("#checkPhoneNumber").isPhoneNumber(this);
            return false;
        }
    </script>
</head>

<body>
    <input type="text" id="checkPhoneNumber" value="ASDFG77" />
    <input type="button" onclick="return validate()" value="Validate" />
</body>

</html>

2. Postal code validation,

<html>

<head>
    //Import jquery.Min.js
    <script type="text/javascript">
        $.fn.isPostalCodeNumber = function(options) {
            intRegex = /^[0-9]{1,4}$/;
            postalcodeNumber = this.val();
            if ((postalcodeNumber.length != 10) || (!intRegex.test(postalcodeNumber))) {
                this.val("");
                this.attr("placeholder", "Invalid Postal Code Number");
                return false;
            }
            return true;
        };

        function validate() {
            $("#checkPostalCodeNumber").isPostalCodeNumber(this);
            return false;
        }
    </script>
</head>

<body>
    <input type="text" id="checkPostalCodeNumber" value="ASDFG77" />
    <input type="button" onclick="return validate()" value="Validate" />
</body>

</html>

3. English validation,

<html>

<head>
    //Import jquery.Min.js
    <script type="text/javascript">
        var englishAlphabetAndWhiteSpace = /^[a-zA-Z ]*$/;
        if (!englishAlphabetAndWhiteSpace.test(this.val())) {
            this.val("");
            this.attr("placeholder", "Invalid English Alphabets");
            return false;
        }
        return true;
        };

        function validate() {
            $("#checkEnglishAlphabets").isEnglishAlphabets(this);
            return false;
        }
    </script>
</head>

<body>
    <input type="text" id="checkEnglishAlphabets" value="ASDFG77" />
    <input type="button" onclick="return validate()" value="Validate" />
</body>

</html>

4. Get the selected value form drop down,

<html>

<head>
    //Import jquery.Min.js
</head>

<body>
    <select id="countries">
<option value="1">India</option>
<option value="2">China</option>
<option value="3">Russia</option>
<option value="4">Srilanka</option>
<option value="5">Pakistan</option>
</select>
    <input type="button" onclick="return getSelected()" value="Get Selected Value" />
    <script type="text/javascript">
        function getSelected() {
            alert($("#countries option:selected").text());
            alert($("#countries").val());
            return false;
        }
    </script>
</body>

</html>