JS实用技巧手记之六

var Cookie = {
    // 读取
    read : function(name){
        var cookieStr = "; "+document.cookie+"; ";
        var index = cookieStr.indexOf("; "+name+"=");
        if (index!=-1){
            var s = cookieStr.substring(index+name.length+3,cookieStr.length);
            return unescape(s.substring(0, s.indexOf("; ")));
        }else{
            return null;
        }
    },
    // 设置
    set : function(name,value,expires){
        var expDays = expires*24*60*60*1000;
        var expDate = new Date();
        expDate.setTime(expDate.getTime()+expDays);
        var expString = expires ? "expires="+expDate.toGMTString() : "";
        var pathString = ";path=/";
        document.cookie = name + "=" + escape(value) + expString + pathString;
    },
    // 删除
    del : function(name){
        var exp = new Date(new Date().getTime()-1);
        var s=this.read(name);
        if(s!=null) {
            document.cookie= name + "="+s+"expires="+exp.toGMTString()+";path=/"
        }
    }
};
// demo:
Cookie.set("xuanfengge", "www.xuanfengge.com", 7);
alert(Cookie.read("xuanfengge"));
Cookie.del("xuanfengge");

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var Cookie = {

// 读取

read : function(name){

var cookieStr = "; "+document.cookie+"; ";

var index = cookieStr.indexOf("; "+name+"=");

if (index!=-1){

var s = cookieStr.substring(index+name.length+3,cookieStr.length);

return unescape(s.substring(0, s.indexOf("; ")));

}else{

return null;

}

},

// 设置

set : function(name,value,expires){

var expDays = expires*24*60*60*1000;

var expDate = new Date();

expDate.setTime(expDate.getTime()+expDays);

var expString = expires ? "expires="+expDate.toGMTString() : "";

var pathString = ";path=/";

document.cookie = name + "=" + escape(value) + expString + pathString;

},

// 删除

del : function(name){

var exp = new Date(new Date().getTime()-1);

var s=this.read(name);

if(s!=null) {

document.cookie= name + "="+s+"expires="+exp.toGMTString()+";path=/"

}

};

// demo:

Cookie.set("xuanfengge", "www.xuanfengge.com", 7);

alert(Cookie.read("xuanfengge"));

Cookie.del("xuanfengge");

var aString = "Hello!";
var bString = new String("Hello!");
if( aString == "Hello!" ){ } //结果: true
if( aString == bString ){ } //结果: true
if( aString === bString ){ } //结果: false (两个对不同,尽管它们的值相同)

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var aString = "Hello!";

var bString = new String("Hello!");

if( aString == "Hello!" ){ } //结果: true

if( aString == bString ){ } //结果: true

if( aString === bString ){ } //结果: false (两个对不同,尽管它们的值相同)

var myString = "hello everybody.";
// 如果检索不到会返回-1,检索到的话返回在该串中的起始位置 
if( myString.indexOf("every") > -1 ){ } //结果: true

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var myString = "hello everybody.";

// 如果检索不到会返回-1,检索到的话返回在该串中的起始位置

if( myString.indexOf("every") > -1 ){ } //结果: true

var myString = "I is your father.";
var result = myString.replace("is","am"); //结果: "I am your father."

1 2	var myString = "I is your father."; var result = myString.replace("is","am"); //结果: "I am your father."

//截取第 6 位开始的字符
var myString = "Every good boy does fine.";
var section = myString.substring(6); //结果: "good boy does fine."
//截取第 0 位开始至第 10 位为止的字符
var myString = "Every good boy does fine.";
var section = myString.substring(0,10); //结果: "Every good"
//截取从第 11 位到倒数第 6 位为止的字符
var myString = "Every good boy does fine.";
var section = myString.slice(11,-6); //结果: "boy does"
//从第 6 位开始截取长度为 4 的字符
var myString = "Every good boy does fine.";
var section = myString.substr(6,4); //结果: "good"

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//截取第 6 位开始的字符

var myString = "Every good boy does fine.";

var section = myString.substring(6); //结果: "good boy does fine."

//截取第 0 位开始至第 10 位为止的字符

var myString = "Every good boy does fine.";

var section = myString.substring(0,10); //结果: "Every good"

//截取从第 11 位到倒数第 6 位为止的字符

var myString = "Every good boy does fine.";

var section = myString.slice(11,-6); //结果: "boy does"

//从第 6 位开始截取长度为 4 的字符

var myString = "Every good boy does fine.";

var section = myString.substr(6,4); //结果: "good"

function fucCheckLength(strTemp){
    var i,sum;
    sum=0;
    for(i=0;i<strTemp.length;i++){
        if ((strTemp.charCodeAt(i)>=0) && (strTemp.charCodeAt(i)<=255)){
            sum=sum+1;
        }else{
            sum=sum+2;
        }
    }
    return sum;
}
// demo:
fucCheckLength("qwe");        //3
fucCheckLength("轩枫");        //4

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function fucCheckLength(strTemp){

var i,sum;

sum=0;

for(i=0;i<strTemp.length;i++){

if ((strTemp.charCodeAt(i)>=0) && (strTemp.charCodeAt(i)<=255)){

sum=sum+1;

}else{

sum=sum+2;

}

return sum;

}

// demo:

fucCheckLength("qwe"); //3

fucCheckLength("轩枫"); //4

//合法日期：yyyy-mm-dd,分隔符可以为-/.
String.prototype.isDate = function() {
    var year,month,date,day;
    var reg = /^([12]\d{3})([-\/\.])([01]?\d)\2([0-3]?\d)$/;
    
    if (!reg.test(this)) return false;
    
    year  = RegExp.$1.parseInt();
    month = RegExp.$3.parseInt() - 1;
    date  = RegExp.$4.parseInt();
    day = new Date(year,month,date);
    
    return ((date == day.getDate()) && (month == day.getMonth()));
}
// demo:
"1999-12-20".isDate()
// 合法日期：yyyy-mm-dd,分隔符可以为-/

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//合法日期：yyyy-mm-dd,分隔符可以为-/.

String.prototype.isDate = function() {

var year,month,date,day;

var reg = /^([12]\d{3})([-\/\.])([01]?\d)\2([0-3]?\d)$/;

if (!reg.test(this)) return false;

year = RegExp.$1.parseInt();

month = RegExp.$3.parseInt() - 1;

date = RegExp.$4.parseInt();

day = new Date(year,month,date);

return ((date == day.getDate()) && (month == day.getMonth()));

}

// demo:

"1999-12-20".isDate()

// 合法日期：yyyy-mm-dd,分隔符可以为-/

function dateDiff(date1,date2) {
    var year,month,date,day1,day2;
    var reg = /^(\d{4})([-\/\.])(\d{2})\2(\d{2})$/;
 
    reg.test(date1);
    year  = RegExp.$1.parseInt();
    month = RegExp.$3.parseInt() - 1;
    date  = RegExp.$4.parseInt();
    day1 = new Date(year,month,date);
 
    reg.test(date2);
    year  = RegExp.$1.parseInt();
    month = RegExp.$3.parseInt() - 1;
    date  = RegExp.$4.parseInt();
    day2 = new Date(year,month,date);
 
    return (day1.getTime() - day2.getTime()) / 86400000;
}
// demo:
// 用以前，先用isDate()判断一下是否合法日期
// 注意：这个函数的reg和isDate()里的reg小you不同
// 以天为单位(date1-date2=?),可以用来比较2个日期大小

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function dateDiff(date1,date2) {

var year,month,date,day1,day2;

var reg = /^(\d{4})([-\/\.])(\d{2})\2(\d{2})$/;

reg.test(date1);

year = RegExp.$1.parseInt();

month = RegExp.$3.parseInt() - 1;

date = RegExp.$4.parseInt();

day1 = new Date(year,month,date);

reg.test(date2);

year = RegExp.$1.parseInt();

month = RegExp.$3.parseInt() - 1;

date = RegExp.$4.parseInt();

day2 = new Date(year,month,date);

return (day1.getTime() - day2.getTime()) / 86400000;

}

// demo:

// 用以前，先用isDate()判断一下是否合法日期

// 注意：这个函数的reg和isDate()里的reg小you不同

// 以天为单位(date1-date2=?),可以用来比较2个日期大小

function isEmpty(obj){
    for(var key in obj){
        return false;
    }
    return true;
}
// demo:
isEmpty({});    //true
isEmpty({"key":"value"});    //false
// jq版本
$.isEmptyObject({});    //true
$.isEmptyObject({"key", "value"});    //false

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function isEmpty(obj){

for(var key in obj){

return false;

}

return true;

}

// demo:

isEmpty({}); //true

isEmpty({"key":"value"}); //false

// jq版本

$.isEmptyObject({}); //true

$.isEmptyObject({"key", "value"}); //false

Object.prototype.length = function() {
    var count = 0;
    for(var i in this){
        count ++;
    }
    return count;
};
// demo：
var a = {a:1, b:2, c:3, d:4};
alert(a.length());    // 5

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Object.prototype.length = function() {

var count = 0;

for(var i in this){

count ++;

}

return count;

};

// demo：

var a = {a:1, b:2, c:3, d:4};

alert(a.length()); // 5

JS实用技巧手记之六

1. 封装cookie组件

2. 字符串比较

3. 检索字符串

4. 查找替换字符串

5. 截取字符串

6. 字数统计(中英文)

7. 字符串是否合法日期

8. 返回两个日期之间的时间间隔

9. 判断是否为空对象

10. 获取对象的属性个数