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JavaScript实现计算器功能

2014-08-05 08:40 579 查看
截图 :



cal.js

Js代码


var Class = {} ;

Class.calculation = function(){

var calculation = {} ;

calculation.result = 0 ;

calculation.calculate = function(num1,num2){} ;

calculation.getResult = function(){

return this.result ;

} ;

return calculation ;

} ;

Class.add = function(){

var add = Class.calculation() ;

add.calculate = function(num1,num2){

this.result = num1 + num2 ;

} ;

return add ;

}

Class.subtraction = function(){

var subtraction = Class.calculation() ;

subtraction.calculate = function(num1,num2){

this.result = num1 - num2 ;

} ;

return subtraction ;

}

Class.multiply = function(){

var multiply = Class.calculation() ;

multiply.calculate = function(num1,num2){

this.result = num1 * num2 ;

} ;

return multiply ;

}

Class.divide = function(){

var divide = Class.calculation() ;

divide.calculate = function(num1,num2){

this.result = num1 / num2 ;

} ;

return divide ;

}

Class.calculator = function(num1,num2,op){

var obj = null ;

var num1 = parseInt(num1) || 0 ;

var num2 = parseInt(num2) || 0 ;

if("+" == op){

obj = Class.add() ;

}

else if("-" == op){

obj = Class.subtraction() ;

}

else if("*" == op){

obj = Class.multiply() ;

}

else if("/" == op){

if(0 == num2){

alert("除数不能为零!") ;

return ;

}

obj = Class.divide() ;

}

else{

alert("无效的" + op + "操作符!") ;

return ;

}

obj.calculate(num1,num2) ;

alert("计算结果:" + obj.getResult()) ;

}

测试 :

Html代码


<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN">

<HTML>

<HEAD>

<TITLE>JavaScript面向对象</TITLE>

<script type="text/javascript" src="js-lib/cal.js"></script>

<script type="text/javascript">

window.onload = function(){

document.getElementById("command").onclick = function(){

var n1 = document.getElementById("n1").value ;

var opera = document.getElementById("opera").value ;

var n2 = document.getElementById("n2").value ;

Class.calculator(n1,n2,opera) ;

}

} ;

</script>

</HEAD>

<BODY>

操作数1 : <input type="text" id="n1" /></br></br>

操作符号 : <input size="4" type="text" id="opera" /></br></br>

操作数2 : <input type="text" id="n2" /></br></br>

<input type="button" id="command" value="计算" />

</BODY>

</HTML>
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