仿造购物网站购买内容数量加减框

效果图：

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代码：

var calculator = function(obj){

this.obj = obj;

this.maxValue = obj.maxValue;

this.minValue = obj.minValue;

this.operationSymbol = obj.operationSymbol;

this.increasing = obj.increasing;

this.init(); //Initialization function

};

calculator.prototype = {

constructor : this,

init : function(){

var _this = this;

if(_this.obj.obj.val() > _this.maxValue || isNaN(_this.obj.obj.val()) != false){

_this.obj.obj.val(_this.maxValue);

return;

}

switch(_this.operationSymbol){

case 'plus':

_this.plus(_this.obj, _this.increasing);

break;

case 'minus':

_this.minus(_this.obj, _this.increasing);

break;

case 'times':

_this.times(_this.obj, _this.increasing);

break;

case 'divide':

_this.divide(_this.obj, _this.increasing);

break;

defaults :

break;

}

},

plus : function(obj,increasing){

var puls_this = this;

puls_this.initValue = parseInt(obj.obj.val());

if(puls_this.initValue >= puls_this.minValue && puls_this.initValue != puls_this.maxValue && isNaN(puls_this.initValue)==false){

obj.obj.val(parseInt(puls_this.initValue + puls_this.increasing));

}

},

minus : function(obj,increasing){

var minus_this = this;

minus_this.initValue = obj.obj.val();

if(minus_this.initValue != minus_this.minValue && isNaN(minus_this.initValue)==false)

obj.obj.val(parseInt(minus_this.initValue - minus_this.increasing));

},

times : function(obj,increasing){

var times_this = this;

times_this.initValue = obj.obj.val();

if(isNaN(times_this.initValue)==false)

obj.obj.val(parseInt(times_this.initValue * times_this.increasing));

},

divide : function(obj,increasing){

var divide_this = this;

divide_this.initValue = obj.obj.val();

if(isNaN(divide_this.initValue) == false)

obj.obj.val(parseInt(divide_this.initValue / divide_this.increasing));

}

};

window.calculator = calculator;

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