JavaScript Calculator – Basic
<html> <head> </head> <body> <!-- Calculator START ########## --> <FORM NAME="Calc"> <TABLE BORDER=1> <TR> <TD> <!-- input box is disabled, you have to use only buttons, not keyboard --> <INPUT TYPE="text" NAME="Input" Size="16" disabled> <br> </TD> </TR> <TR> <TD> <!-- On mouse click += (append to) form Calc>Input box the value between ' ' --> <INPUT TYPE="button" NAME="one" VALUE=" 1 " OnClick="Calc.Input.value += '1'"> <INPUT TYPE="button" NAME="two" VALUE=" 2 " OnCLick="Calc.Input.value += '2'"> <INPUT TYPE="button" NAME="three" VALUE=" 3 " OnClick="Calc.Input.value += '3'"> <!-- Notice the space before and after the math operator, you have to write 1 + 1 not 1+1 --> <INPUT TYPE="button" NAME="plus" VALUE=" + " OnClick="Calc.Input.value += ' + '"> <br> <INPUT TYPE="button" NAME="four" VALUE=" 4 " OnClick="Calc.Input.value += '4'"> <INPUT TYPE="button" NAME="five" VALUE=" 5 " OnCLick="Calc.Input.value += '5'"> <INPUT TYPE="button" NAME="six" VALUE=" 6 " OnClick="Calc.Input.value += '6'"> <INPUT TYPE="button" NAME="minus" VALUE=" - " OnClick="Calc.Input.value += ' - '"> <br> <INPUT TYPE="button" NAME="seven" VALUE=" 7 " OnClick="Calc.Input.value += '7'"> <INPUT TYPE="button" NAME="eight" VALUE=" 8 " OnCLick="Calc.Input.value += '8'"> <INPUT TYPE="button" NAME="nine" VALUE=" 9 " OnClick="Calc.Input.value += '9'"> <INPUT TYPE="button" NAME="times" VALUE=" x " OnClick="Calc.Input.value += ' * '"> <br> <INPUT TYPE="button" NAME="clear" VALUE=" c " OnClick="Calc.Input.value = ''"> <INPUT TYPE="button" NAME="zero" VALUE=" 0 " OnClick="Calc.Input.value += '0'"> <!-- eval(Calc.Input.value) is interpreting the value of your input as Javascript. So when there would be 4 + 6 in the input, it'll be evaluated as Javascript and return 10. --> <INPUT TYPE="button" NAME="DoIt" VALUE=" = " OnClick="Calc.Input.value = eval(Calc.Input.value)"> <INPUT TYPE="button" NAME="div" VALUE=" / " OnClick="Calc.Input.value += ' / '"> <br> </TD> </TR> </TABLE> </FORM> <!-- Calculator END ########## --> </body> </html>DEMO
