分享原生JavaScript技巧大收集(1~10)

1、原生JavaScript实现字符串长度截取

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 + "..."

}

2、原生JavaScript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;

}

3、原生JavaScript清除空格

String.prototype.trim = function() {

    var reExtraSpace = /^\s*(.*?)\s+$/;

    return this.replace(reExtraSpace, "$1")

}

4、原生JavaScript替换全部

String.prototype.replaceAll = function(s1, s2) {

    return this.replace(new RegExp(s1, "gm"), s2)

}

5、原生JavaScript转义html标签

function HtmlEncode(text) {

    return text.replace(/&/g, '&').replace(/\"/g, '"').replace(//g, '>')

}

6、原生JavaScript还原html标签

function HtmlDecode(text) {

    return text.replace(/&/g, '&').replace(/"/g, '\"').replace(//g, '>')

}

7、原生JavaScript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

}

8、原生JavaScript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

    }

}

9、原生JavaScript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=360doc.com;"

}

10、原生JavaScript获取cookie值

function getCookie(name) {

    var arr = document.cookie.match(new RegExp("(^| )" + name + "=([^;]*)(;|$)"));

    if (arr != null) return unescape(arr[2]);

    return null

}

文章来源：jquery教程 - http://www./Show.aspx?id=300