Form Validation Using Javascript and Regular Expressions

Hi Guys,

 I was working in asp.net, There was a signup form and client wanted sophisticated validations on the form at the client side. Using validations was a cumbersome task as it requires complexities and user inputs.

I managed to create my own javascript file which validates any form and html controls by the use of the "name" attribute of the tag. You need to pass the div name which has the form or html controls which you want to validate.  In this example my form was in the html table, You can customize the javascript code based on the parent elements.

Here is my javascript file, Which must be included in the page to validate the page.

 /*---------------------------------Javascript Code Starts Here-------------------------------*/
//matches only characters, no special characters and range is from 3-50 characters
        //var match_first_name = /^([a-zA-Z]+){3,50}$/;

        //matches only characters, no special characters and range is from 2-50 characters.
        //Added the constraint of non required number after first name [space] [any number].
        var match_first_name = /^(([a-zA-Z]+){3,50})(\s\S\d{0,1})?$/;

        //matches only characters, no special characters and range is from 2-50 characters.
        //Added the constraint of non required number after first name [space] [any number].
        var match_last_name = /^(([a-zA-Z]+){3,50})(\s\S\d{0,1})?$/;

        //matches email, no special characters and name range is 1 to 250 then domain characters are from 1 to 250 and (.in .com) i.e 2 to 3 characters can be there.
        var match_email = /^((([a-zA-z]+(\.[a-zA-z0-9])?){1,250})(\d{0,30})?)\@((([a-zA-z]+){1,250}))\.(([a-zA-z]+){2,5})$/;

        //matches phone number in the format (223) 323-3726 i.e (xxx) xxx-xxxx. Only 14 characters can be added
        var match_phone = /^(\(\d{3}\)\s\d{3}\-\d{4})$/;

        //matches the password the password can have special characters as well as numbers.
        //var match_password = /^([a-zA-Z0-9@!#$%*&^.]{8,30})$/;

        //matches the password having any string 4 to 8 characters
        //var match_password = /^.{4,8}$/;

        //matches the password expression that requires one lower case letter, one upper case letter, one digit, 6-33 length, and no spaces.
        var match_password = /^(?=.*\d)(?=.*[a-z])(?=.*[A-Z])(?!.*\s).{6,33}$/;

        //matches the height and can have numeric or decimal values in the range of xx.xx
        var match_height = /^[0-9]{1,2}((\.)\d{0,2})?$/

        //matches the height and can have numeric or decimal values in the range of xx.xx
        var match_weight = /^[0-9]{1,3}((\.)\d{0,2})?$/

        var count = 0;

        function check(divname, showerrmsg) {
            var val = '';
            var result = true;
            var pwd = '';
            $("#" + divname + " table input").each(function (index, el) {
                val = $(el).val();
                if (($(el).attr('name').indexOf('FirstName') != -1) || ($(el).attr('name').indexOf('firstname') != -1)) {
                    result = match_first_name.test(val);
                    if (result == false) {
                        $(el).addClass("error");

                        if (showerrmsg == true)
                            alert('Incorrect name format, Please enter more than 2 and less than 50 characters without any numbers, spaces or special characters.');

                        return false;
                    }
                    else {
                        $(el).removeClass("error");
                    }
                }
                else if (($(el).attr('name').indexOf('LastName') != -1) || ($(el).attr('name').indexOf('lastname') != -1)) {
                    result = match_last_name.test(val);
                    if (result == false) {
                        $(el).addClass("error");

                        if (showerrmsg == true)
                            alert('Incorrect name format, Please enter more than 2 and less than 50 characters without any numbers, spaces or special characters.');

                        return false;
                    }
                    else {
                        $(el).removeClass("error");
                    }
                }
                else if (($(el).attr('name').indexOf('Email') != -1) || ($(el).attr('name').indexOf('email') != -1)) {
                    result = match_email.test(val);
                    if (result == false) {
                        $(el).addClass("error");

                        if (showerrmsg == true)
                            alert('Please enter a valid email address.');

                        return false;
                    }
                    else {
                        $(el).removeClass("error");
                    }
                }
                else if (($(el).attr('name').indexOf('Phone') != -1) || ($(el).attr('name').indexOf('phone') != -1)) {
                    result = match_phone.test(val);
                    if (result == false) {
                        $(el).addClass("error");

                        if (showerrmsg == true)
                            alert('Please enter valid US phone number. eg. (xxx) xxx-xxxx');

                        return false;
                    }
                    else {
                        if (val == "(000) 000-0000") {

                            if (showerrmsg == true)
                                alert("Invalid Phone Number");

                            $(el).addClass("error");
                            result = false;
                            return false;
                        }
                        else {
                            $(el).removeClass("error");
                        }
                    }
                }
                else if (($(el).attr('name').indexOf('ConfirmPassword') != -1) || ($(el).attr('name').indexOf('confirmpassword') != -1)) {
                    result = match_password.test(val);
                                       if (val == pwd) {
                        $(el).removeClass("error");
                    }
                    else {

                        if (showerrmsg == true)
                            alert("Password Doesn't Match");

                        result = false;
                        $(el).addClass("error");
                        return false;
                    }
                }
                else if (($(el).attr('name').indexOf('Password') != -1) || ($(el).attr('name').indexOf('password') != -1)) {
                    pwd = val;
                    result = match_password.test(val);
                    if (result == false) {
                        $(el).addClass("error");

                        if (showerrmsg == true)
                            alert('Please enter valid password having 6 to 13 characters, One lower case letter, one upper case letter and one digit.');

                        return false;
                    }
                    else {
                        $(el).removeClass("error");
                    }
                }
                else if (($(el).attr('name').indexOf('height') != -1) || ($(el).attr('name').indexOf('height') != -1)) {
                    result = match_height.test(val);

                    var msg = 'Please enter valid height. eg. xx.xx';
                    if (result != false) {
                        if (eval($(el).val()) <= 0) {
                            msg = 'Height cannot be zero.';
                            result = false;
                        }
                    }

                    if (result == false) {
                        $(el).addClass("error");

                        if (showerrmsg == true)
                            alert(msg);

                        return false;
                    }
                    else {
                        $(el).removeClass("error");
                    }
                }
                else if (($(el).attr('name').indexOf('weight') != -1) || ($(el).attr('name').indexOf('weight') != -1)) {
                    result = match_weight.test(val);
                    var msg = 'Please enter valid weight. eg. xxx.xx';
                    if (result != false) {
                        if (eval($(el).val()) <= 0) {
                            msg = 'Weight cannot be zero.';
                            result = false;
                        }
                    }

                    if (result == false) {
                        $(el).addClass("error");

                        if (showerrmsg == true) {
                            alert(msg);
                        }


                        return false;
                    }
                    else {
                        $(el).removeClass("error");
                    }
                }
                else if (($(el).attr('name').indexOf('registeration') != -1) || ($(el).attr('name').indexOf('Registeration') != -1)) {
                    if ($(el).val().trim() == "")
                        result = false;

                    if (result == false) {
                        $(el).addClass("error");

                        if (showerrmsg == true)
                            alert('Please enter registeration number');

                        return false;
                    }
                    else {
                        $(el).removeClass("error");
                    }
                }
                else if (($(el).attr('name').indexOf('image') != -1) || ($(el).attr('name').indexOf('FileUpload') != -1)) {

                    if (showerrmsg) {
                        var _validFileExtensions = [".jpg", ".jpeg", ".bmp", ".gif", ".png"];
                        var oInput = $(el);

                        //Check extension
                        if ($(oInput).attr('type') == "file") {
                            var sFileName = $(oInput).val();
                            if (sFileName.length > 0 || $(el).attr('name') == "FileUpload1") {
                                var blnValid = false;
                                for (var j = 0; j < _validFileExtensions.length; j++) {
                                    var sCurExtension = _validFileExtensions[j];
                                    if (sFileName.substr(sFileName.length - sCurExtension.length, sCurExtension.length).toLowerCase() == sCurExtension.toLowerCase()) {
                                        blnValid = true;
                                        break;
                                    }
                                }
                                if (!blnValid) {
                                    alert("Sorry, Please select a file, having extensions " + _validFileExtensions.join(", ") + " with a maximum size of 1MB.");
                                    $(el).addClass("error");
                                    result = false;
                                    return false;
                                }
                                else {
                                    $(el).removeClass("error");
                                }
                            }
                        }

                        //Check filesize
                        if (window.FileReader) {
                            file = oInput.size;
                            size = file;
                            var files = document.getElementById($(el).attr('id')).files;
                            if (files[0].size > 1048576) {
                                alert('File size should be less than 1MB');
                                result = false;
                            }
                        }
                    } //end of if(showerrmsg)
                }
            });
            showerrmsg = false;
            return result;
        }

        function initialize(divname) {
            $("#" + divname + " table input").each(function (index, el) {

                if($(el).attr("type")!="file")
                    $(el).bind("blur", function () { check(divname, false); });

                if($(el).attr("type")=="submit")
                    $(el).bind("blur", function () { check(divname, true); });
            });

            $("#" + divname + " table input").each(function (index, el) {
                $(el).bind("keydown", function (event) { if (len($(el).val()) > $(el).attr('maxlength')) event.preventDefault(); });
            });
        }
 /*---------------------------------Javascript Code Ends Here-------------------------------*/

To Run the above you need to include the javascript code/file in the page you want your validations. In your page add the following lines

<script>
 $(document).ready({ initialize(your_div_name_having_form);});
</script>

Thanks
Ritesh