要完成此效果把如下代码加入到<body>区域中 <script language="JavaScript"> <!-- Hide the script from old browsers -- function compute(obj) {obj.expr.value = eval(obj.expr.value)} var one = '1' var two = '2' var three = '3' var four = '4' var five = '5' var six = '6' var seven = '7' var eight = '8' var nine = '9' var zero = '0' var plus = '+' var minus = '-' var multiply = '*' var divide = '/' var decimal = '.' function enter(obj, string) {obj.expr.value += string} function clear(obj) {obj.expr.value = ''} // --End Hiding Here --> </script> <form name="calc"> <table border=1> <td colspan=4><input type="text" name="expr" size=30 action="compute(this.form)"> <tr> <td><input type="button" value=" 7 " onClick="enter(this.form, seven)"> <td><input type="button" value=" 8 " onClick="enter(this.form, eight)"> <td><input type="button" value=" 9 " onClick="enter(this.form, nine)"> <td><input type="button" value=" / " onClick="enter(this.form, divide)"> <tr><td><input type="button" value=" 4 " onClick="enter(this.form, four)"> <td><input type="button" value=" 5 " onClick="enter(this.form, five)"> <td><input type="button" value=" 6 " onClick="enter(this.form, six)"> <td><input type="button" value=" * " onClick="enter(this.form, multiply)"> <tr><td><input type="button" value=" 1 " onClick="enter(this.form, one)"> <td><input type="button" value=" 2 " onClick="enter(this.form, two)"> <td><input type="button" value=" 3 " onClick="enter(this.form, three)"> <td><input type="button" value=" - " onClick="enter(this.form, minus)"> <tr><td colspan=2><input type="button" value=" 0 " onClick="enter(this.form, zero)"> <td><input type="button" value=" . " onClick="enter(this.form, decimal)"> <td><input type="button" value=" + " onClick="enter(this.form, plus)"> <tr><td colspan=2><input type="button" value=" = " onClick="compute(this.form)"> <td colspan=2><input type="button" value="AC" size= 3 onClick="clear(this.form)"> </table> </form>