Useful JavaScript Functions

Useful JavaScript functions

1. Comma separator/formatter function:

It will useful represent numbers in comma separated format. 

E.g. 

Input: 1415135                                              Output: 14,15,135

function commaFormatter(Num) {

        if (Num.length > 3) {

            Num += '';

            Num = Num.replace(new RegExp(",", "g"), "")

            x = Num.split('.');

            x1 = x[0];

            x2 = x.length > 1 ? '.' + x[1] : '';

            var rgx = /(\d+)(\d{2})/;

            last3 = x1.slice(-3);

            var k = x1.slice(0, x1.length - 3);

            var p = k.substring(0, x1.length - 3);

            while (rgx.test(parseInt(p)))

                p = p.replace(rgx, '$1' + ',' + '$2');

            i = p + "," + last3 + x2;

            if (i.length == 4)

                return i.slice(-3);

            else

                return i;

        }

        else

            return Num;

    }

How to call

<input type="text" name="price" id="price" onkeyup="javascript:this.value= commaFormatter(this.value);"/>

2. To allow only numeric character function:

It will useful to restrict user to enter numeric characters only

function isNumberKey(evt) {

                var charCode = (evt.which) ? evt.which : event.keyCode;

                if (charCode > 31 && (charCode < 47 || charCode > 57 || charCode==47 ))

                                return false;

                return true;

}

How to call

<input type="text" name="age" id="age" onkeypress="return isNumberKey(event)" />

3. To allow only alphabets function:

It will useful to restrict user to enter alphabets characters only

function isCharacterKey(evt) {

                var charCode = (evt.which) ? evt.which : event.keyCode;

                if (charCode > 32 && (charCode < 65 || charCode > 90) && (charCode < 97 || charCode > 122))

                                return false;

                return true;

}

How to call

<input type="text" name="name" id="name" onkeypress="return isCharacterKey(event)" />

4. To allow only alpha-numeric function:

It will useful to restrict user to enter alpha-numeric characters only

function isAlphaNumKey(evt) {

                var charCode = (evt.which) ? evt.which : event.keyCode;

                //alert(charCode);

                if (charCode > 31 && (charCode < 47 || charCode > 57 || charCode==47 ) && (charCode < 65 || charCode > 90) && (charCode < 97 || charCode > 122))

                                return false;

                return true;

}

How to call

<input type="text" name="registrationNo" id=" registrationNo " onkeypress="return isAlphaNumKey(event)" />

  

5. To validate email ID:

It will useful for email ID validation

function validateEmail(email) {

                var mailformat = /^\w+([\.-]?\w+)*@\w+([\.-]?\w+)*(\.\w{2,3})+$/;

                if(!email.value.match(mailformat))  {

                                return false;

                }

                return true;

}

How to call

<input type="text" name="emailId" id=" emailId " onblur="return validateEmail(this.value)" />

 6. To validate date:

It will useful to validate whether date is valid or not. And also checks the format as well (mm/dd/yyyy format).

Note: If you want other date format than make the required changes.

function isDate(obj) {

                var currVal = jqEditBacklog(obj).val();

                if(currVal == '')

                                return false;

                var rxDatePattern = /^(\d{2})(\/)(\d{1,2})(\/)(\d{1,4})$/; //Declare Regex

                var dtArray = currVal.match(rxDatePattern); // is format OK?

                if (dtArray == null)

                    return false;

   //Checks for mm/dd/yyyy format.

   dtMonth = dtArray[3];

   dtDay= dtArray[5];

   dtYear = dtArray[1];       

   if (dtMonth < 1 || dtMonth > 12)

       return false;

   else if (dtDay < 1 || dtDay> 31)

       return false;

   else if ((dtMonth==4 || dtMonth==6 || dtMonth==9 || dtMonth==11) && dtDay ==31)

       return false;

   else if (dtMonth == 2)

   {

       var isleap = (dtYear % 4 == 0 && (dtYear % 100 != 0 || dtYear % 400 == 0));

       if (dtDay> 29 || (dtDay ==29 && !isleap))

               return false;

   }

   return true;

}

How to call

<input type="text" name="dob" id=" dob" onkeypress="return isDate(event);" />