Modifies a number by adding commas after every third digit. For example, 123456789 is converted to 123,456,789. The script example shows this JavaScript as used on numbers of various sizes. And, it demonstrates a clever use of the modulus operator.

Calculates resistance from colors and colors from resistance, each with image-based output. Both color and numeric interfaces function as input and output.

Trying to keep track of gasoline expenses? This JavaScript calculates how many miles you are getting per gallon - per day and per year. It also calculates the amount spent per year and how much CO2 your car is producing.

Calculate whether or not a number is prime and break it into its prime factors. Also includes a loading bar for large numbers.

Convert units from one to another. Simply choose the unit you want to use, type the value in the field next to it, and click the 'Convert' button.

This calculator code can quickly determine the Greatest Common Factor and Least Common Multiplier between two or three numbers.

This JavaScript enables you to set a fixed number of decimal places for an input number. It also provides error checking.

A function to sum input boxes and display in text rounded to two places with dollar sign. It also sends result with submit and has a reset.

Formats phone number to the standard (xxx)xxx-xxxx format. This JavaScript will first eliminate all non-numeral values and check to see whether the value is a valid 10 digit long phone number. If it is, the number is formatted with the parenthesis and the dash and returns the value to the phone number textbox. If less than 10 numbers, a blank value is returned and an error message shows up.

Use this JavaScript to calculate your BMI (Body Mass Index). Measurements are computed using the metric system. A perfect addition for a health Web site.