Javascript-javascript tutorial

Write a "Personal Income Tax calculator" in javascript scripting language "? Calculation formula: Income Tax (Monthly Income-threshold) * 10%; fill in again to clear all; very practical, small partner can refer.

TABLE {    BORDER-RIGHT: medium none; PADDING-RIGHT: 0px; BORDER-TOP: medium none; PADDING-LEFT: 0px; PADDING-BOTTOM: 0px; MARGIN: 0px; BORDER-LEFT: medium none; PADDING-TOP: 0px;

CSS:

BORDER-BOTTOM: medium none}TD {    BORDER-RIGHT: medium none; PADDING-RIGHT: 0px; BORDER-TOP: medium none; PADDING-LEFT: 0px; PADDING-BOTTOM: 0px; MARGIN: 0px; BORDER-LEFT: medium none; PADDING-TOP: 0px;BORDER-BOTTOM: medium none}IMG {    BORDER-RIGHT: medium none; PADDING-RIGHT: 0px; BORDER-TOP: medium none; PADDING-LEFT: 0px; PADDING-BOTTOM: 0px; MARGIN: 0px; BORDER-LEFT: medium none; PADDING-TOP: 0px;BORDER-BOTTOM: medium none}FORM {    BORDER-RIGHT: medium none; PADDING-RIGHT: 0px; BORDER-TOP: medium none; PADDING-LEFT: 0px; PADDING-BOTTOM: 0px; MARGIN: 0px; BORDER-LEFT: medium none; PADDING-TOP: 0px;BORDER-BOTTOM: medium none}TD {    FONT-SIZE: 12px}P {    FONT-SIZE: 12px}LI {    FONT-SIZE: 12px}SELECT {    FONT-SIZE: 12px}INPUT {    FONT-SIZE: 12px}TEXTAREA {    FONT-SIZE: 12px}SELECT {    BORDER-RIGHT: #49b8e3 1px solid; BORDER-TOP: #49b8e3 1px solid; BORDER-LEFT: #49b8e3 1px solid; BORDER-BOTTOM: #49b8e3 1px solid; BACKGROUND-COLOR: #e2f4ff}INPUT {    BORDER-RIGHT: #49b8e3 1px solid; BORDER-TOP: #49b8e3 1px solid; BORDER-LEFT: #49b8e3 1px solid; BORDER-BOTTOM: #49b8e3 1px solid; BACKGROUND-COLOR: #e2f4ff}TEXTAREA {    BORDER-RIGHT: #49b8e3 1px solid; BORDER-TOP: #49b8e3 1px solid; BORDER-LEFT: #49b8e3 1px solid; BORDER-BOTTOM: #49b8e3 1px solid; BACKGROUND-COLOR: #e2f4ff}.f14 {    FONT-SIZE: 14px}.lh19 {    LINE-HEIGHT: 19px}A:hover {    COLOR: #ff0000}.b1 {    BORDER-RIGHT: #000000 1px solid; BORDER-TOP: #000000 1px solid; BORDER-LEFT: #000000 1px solid; BORDER-BOTTOM: #000000 1px solid}.b2 {    BORDER-BOTTOM: #ffffff 1px solid}.b3 {    BORDER-RIGHT: #cfe9f8 5px solid; BORDER-TOP: #cfe9f8 5px solid; BORDER-LEFT: #cfe9f8 5px solid; BORDER-BOTTOM: #cfe9f8 5px solid}.cRed {    COLOR: #cc0000}.cGary {    COLOR: #6c6c6c}.cBlue {    COLOR: #066cd2}.linkBlankUl A:link {    COLOR: #000; TEXT-DECORATION: underline}.linkBlankUl A:visited {    COLOR: #000; TEXT-DECORATION: underline}.linkBlankUl A:active {    COLOR: #f00; TEXT-DECORATION: underline}.linkBlankUl A:hover {    COLOR: #f00; TEXT-DECORATION: underline}.linkBlank A:link {    COLOR: #000; TEXT-DECORATION: none}.linkBlank A:visited {    COLOR: #000; TEXT-DECORATION: none}.linkBlank A:active {    COLOR: #f00; TEXT-DECORATION: none}.linkBlank A:hover {    COLOR: #f00; TEXT-DECORATION: none}.linkRed {    COLOR: #7b0000}.linkRed A:link {    COLOR: #7b0000; text-: none}.linkRed A:visited {    COLOR: #7b0000; text-: none}.linkRed A:active {    COLOR: #7b0000; text-: underline}.linkRed A:hover {    COLOR: #7b0000; text-: underline}.linkBlue A:link {    COLOR: #003399; TEXT-DECORATION: underline}.linkBlue A:visited {    COLOR: #003399; TEXT-DECORATION: underline}.linkBlue A:active {    COLOR: #0268ce; TEXT-DECORATION: underline}.linkBlue A:hover {    COLOR: #0268ce; TEXT-DECORATION: underline}

HTML: