< span style> table{height: 350px; width: 270px; text-align: center; } input{ height: 100%; width: 350px; font-size: </style><body> <table border="1" align="center" bgColor="#bbff77" >< tr> < TD colspan="4"> <input type="text" Id = "nummessege" / > < / td > < / tr > < tr > < td onclick = "onclicknum (1)" > 1 < / td > < td onclick = "onclicknum (2)" > 2 < / td > < td onclick = "onclicknum (3)" > 3 < / td > < td onclick = "onclicknum (' + ')" > + < / td > < / tr > < tr > < td Onclick =" onClickNum (4)"> 4 </td> <td onclick=" onClickNum (5)"> 5 </ TD > < td onclick = "onclicknum (' - ')" > - < / td > < / tr > < tr > < td onclick = "onclicknum (7)" > 7 < / td > < td 8 "onclick =" onclicknum (8) > < / td > < td onclick = "onclicknum (9)" > 9 < / td > < td onclick = "onclicknum (' * ')" > * < / td > < / tr > < tr > < td colspan = "2" onclick = "onclicknum (0)" > 0 < / td > < td onclick = "onclicknum ('. ')" >. < / td > < td "Onclick =" onclicknum ('/') > / < / td > < / tr > < tr > < td colspan = "2" onclick = "onclickclear ()" > Del < / td > < td Colspan ="2" onclick=" onClickResult ()"> = </td> </tr> </table> </body> <script type="text/javascript"> var Numresult; Var STR. Function onClickNum (nums) {STR = document.getElementById("nummessege"); Value = str.value + nums; }, function onClickClear () {STR = document.getelementById ("nummessege"); STR. Value = ' '; }, function onClickResult () {STR = document.getelementById ("nummessege"); Numresult = eval (STR) value); STR. Value = numresult; } </script>Copy the code