| 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>
 |