js 常用函数代码片段

//字符串长度截取
function cutstr(str, len) {
    var temp;
    var icount = 0;
    var patrn = /[^\x00-\xff]/;
    var strre = "";
    for (var i = 0; i < str.length; i++) {
        if (icount < len - 1) {
            temp = str.substr(i, 1);
            if (patrn.exec(temp) == null) {
                icount = icount + 1
            } else {
                icount = icount + 2
            }
            strre += temp        
        } else {
            break
        }
    }
    return strre + "..."
}
//获取域名主机
function getHost(url) {
    var host = "null";
    if(typeof url == "undefined"|| null == url) {
        url = window.location.href;
    }
    var regex = /^\w+\:\/\/([^\/]*).*/;
    var match = url.match(regex);
    if(typeof match != "undefined" && null != match) {
        host = match[1];
    }
    return host;
}
//清除空格
String.prototype.trim = function() {
    var reExtraSpace = /^\s*(.*?)\s+$/;
    return this.replace(reExtraSpace, "$1")
}
//替换全部
String.prototype.replaceAll = function(s1, s2) {
    return this.replace(new RegExp(s1, "gm"), s2)
}
//转义html标签
function HtmlEncode(text) {
    return text.replace(/&/g, '&').replace(/\"/g, '"').replace(/</g, '<').replace(/>/g, '>')
}

//还原html标签
function HtmlDecode(text) {
    return text.replace(/&/g, '&').replace(/"/g, '\"').replace(/</g, '<').replace(/>/g, '>')
}
//时间日期格式转换
Date.prototype.Format = function(formatStr) {
    var str = formatStr;
    var Week = ['日', '一', '二', '三', '四', '五', '六'];
    str = str.replace(/yyyy|YYYY/, this.getFullYear());
    str = str.replace(/yy|YY/, (this.getYear() % 100) > 9 ? (this.getYear() % 100).toString() : '0' + (this.getYear() % 100));
    str = str.replace(/MM/, (this.getMonth() + 1) > 9 ? (this.getMonth() + 1).toString() : '0' + (this.getMonth() + 1));
    str = str.replace(/M/g, (this.getMonth() + 1));
    str = str.replace(/w|W/g, Week[this.getDay()]);
    str = str.replace(/dd|DD/, this.getDate() > 9 ? this.getDate().toString() : '0' + this.getDate());
    str = str.replace(/d|D/g, this.getDate());
    str = str.replace(/hh|HH/, this.getHours() > 9 ? this.getHours().toString() : '0' + this.getHours());
    str = str.replace(/h|H/g, this.getHours());
    str = str.replace(/mm/, this.getMinutes() > 9 ? this.getMinutes().toString() : '0' + this.getMinutes());
    str = str.replace(/m/g, this.getMinutes());
    str = str.replace(/ss|SS/, this.getSeconds() > 9 ? this.getSeconds().toString() : '0' + this.getSeconds());
    str = str.replace(/s|S/g, this.getSeconds());
    return str
}
//判断是否为数字类型
function isDigit(value) {
    var patrn = /^[0-9]*$/;
    if (patrn.exec(value) == null || value == "") {
        return false
    } else {
        return true
    }
}
//设置cookie值
function setCookie(name, value, Hours) {
    var d = new Date();
    var offset = 8;
    var utc = d.getTime() + (d.getTimezoneOffset() * 60000);
    var nd = utc + (3600000 * offset);
    var exp = new Date(nd);
    exp.setTime(exp.getTime() + Hours * 60 * 60 * 1000);
    document.cookie = name + "=" + escape(value) + ";path=/;expires=" + exp.toGMTString() + ";domain=x.com;"
}
//获取cookie值
function getCookie(name) {
    var arr = document.cookie.match(new RegExp("(^| )" + name + "=([^;]*)(;|$)"));
    if (arr != null) return unescape(arr[2]);
    return null
}

//获取URL中的get参数
function getPar(par){
    //获取当前URL
    var local_url = document.location.href; 
    //获取要取得的get参数位置
    var get = local_url.indexOf(par +"=");
    if(get == -1){
        return false;   
    }   
    //截取字符串
    var get_par = local_url.slice(par.length + get + 1);    
    //判断截取后的字符串是否还有其他get参数
    var nextPar = get_par.indexOf("&");
    if(nextPar != -1){
        get_par = get_par.slice(0, nextPar);
    }
    return get_par;
}
 
/*-实现2(返回 $_GET 对象, 仿PHP模式)---*/
/*第2种方式, 使用时, 可以直接 $_GET['get参数'], 就直接获得GET参数的值*/
var $_GET = (function(){
    var url = window.document.location.href.toString();
    var u = url.split("?");
    if(typeof(u[1]) == "string"){
        u = u[1].split("&");
        var get = {};
        for(var i in u){
            var j = u[i].split("=");
            get[j[0]] = j[1];
        }
        return get;
    } else {
        return {};
    }
})();
/**
 * 获取随机字符串
 */
function getRandomStr(){
	return Math.random().toString(36).substr(2,6)
}