20个最常用的javascript方法函数收集

 

1、字符串长度截取

function cutstr(str, len) {
    var temp,
        icount = 0,
        patrn = /[^x00-xff]/，
        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、替换全部

String.prototype.replaceAll = function(s1, s2) {
    return this.replace(new RegExp(s1, "gm"), s2)
}

3、清除空格

String.prototype.trim = function() {
    var reExtraSpace = /^s*(.*?)s+$/;
    return this.replace(reExtraSpace, "$1")
}

4、清除左空格/右空格

function ltrim(s){ return s.replace( /^(s*|　*)/, ""); } 
function rtrim(s){ return s.replace( /(s*|　*)$/, ""); }

5、判断是否以某个字符串开头

String.prototype.startWith = function (s) {
    return this.indexOf(s) == 0
}

6、判断是否以某个字符串结束

String.prototype.endWith = function (s) {
    var d = this.length - s.length;
    return (d >= 0 && this.lastIndexOf(s) == d)
}

7、转义html标签

function HtmlEncode(text) {
    return text.replace(/&/g, '&').replace(/"/g, '"').replace(/</g, '<').replace(/>/g, '>')
}

8、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
}

9、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
    }
}

10、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;"
}
获取cookie值

function getCookie(name) {
    var arr = document.cookie.match(new RegExp("(^| )" + name + "=([^;]*)(;|$)"));
    if (arr != null) return unescape(arr[2]);
    return null
}

11、加入收藏夹

function AddFavorite(sURL, sTitle) {
    try {
        window.external.addFavorite(sURL, sTitle)
    } catch(e) {
        try {
            window.sidebar.addPanel(sTitle, sURL, "")
        } catch(e) {
            alert("加入收藏失败，请使用Ctrl+D进行添加")
        }
    }
}

12、设为首页

function setHomepage() {
    if (document.all) {
        document.body.style.behavior = 'url(#default#homepage)';
        document.body.setHomePage('http://w3cboy.com')
    } else if (window.sidebar) {
        if (window.netscape) {
            try {
                netscape.security.PrivilegeManager.enablePrivilege("UniversalXPConnect")
            } catch(e) {
                alert("该操作被浏览器拒绝，如果想启用该功能，请在地址栏内输入 about:config,然后将项 signed.applets.codebase_principal_support 值该为true")
                }
        }
        var prefs = Components.classes['@mozilla.org/preferences-service;1'].getService(Components.interfaces.nsIPrefBranch);
        prefs.setCharPref('browser.startup.homepage', 'http://w3cboy.com')
    }
}

13、加载样式文件

function LoadStyle(url) {
    try {
        document.createStyleSheet(url)
    } catch(e) {
        var cssLink = document.createElement('link');
        cssLink.rel = 'stylesheet';
        cssLink.type = 'text/css';
        cssLink.href = url;
        var head = document.getElementsByTagName('head')[0];
        head.appendChild(cssLink)
    }
}

14、返回脚本内容

function evalscript(s) {
    if(s.indexOf('<script') == -1) return s;
    var p = /<script[^>]*?>([^x00]*?)</script>/ig;
    var arr = [];
    while(arr = p.exec(s)) {
        var p1 = /<script[^>]*?src="([^>]*?)"[^>]*?(reload="1")?(?:charset="([w-]+?)")?></script>/i;
        var arr1 = [];
        arr1 = p1.exec(arr[0]);
        if(arr1) {
            appendscript(arr1[1], '', arr1[2], arr1[3]);
        } else {
            p1 = /<script(.*?)>([^x00]+?)</script>/i;
            arr1 = p1.exec(arr[0]);
            appendscript('', arr1[2], arr1[1].indexOf('reload=') != -1);
        }
    }
    return s;
}

15、清除脚本内容

function stripscript(s) {
    return s.replace(/<script.*?>.*?</script>/ig, '');
}

16、动态加载脚本文件

function appendscript(src, text, reload, charset) {
    var id = hash(src + text);
    if(!reload && in_array(id, evalscripts)) return;
    if(reload && $(id)) {
        $(id).parentNode.removeChild($(id));
    }

    evalscripts.push(id);
    var scriptNode = document.createElement("script");
    scriptNode.type = "text/javascript";
    scriptNode.id = id;
    scriptNode.charset = charset ? charset : (BROWSER.firefox ? document.characterSet : document.charset);
    try {
        if(src) {
            scriptNode.src = src;
            scriptNode.onloadDone = false;
            scriptNode.onload = function () {
                scriptNode.onloadDone = true;
                JSLOADED[src] = 1;
             };
             scriptNode.onreadystatechange = function () {
                 if((scriptNode.readyState == 'loaded' || scriptNode.readyState == 'complete') && !scriptNode.onloadDone) {
                    scriptNode.onloadDone = true;
                    JSLOADED[src] = 1;
                }
             };
        } else if(text){
            scriptNode.text = text;
        }
        document.getElementsByTagName('head')[0].appendChild(scriptNode);
    } catch(e) {}
}

17、返回按ID检索的元素对象

function $(id) {
    return !id ? null : document.getElementById(id);
}

18、跨浏览器绑定事件

function addEventSamp(obj,evt,fn){ 
    if(!oTarget){return;}
    if (obj.addEventListener) { 
        obj.addEventListener(evt, fn, false); 
    }else if(obj.attachEvent){ 
        obj.attachEvent('on'+evt,fn); 
    }else{
        oTarget["on" + sEvtType] = fn;
    } 
}

19、跨浏览器删除事件

function delEvt(obj,evt,fn){
    if(!obj){return;}
    if(obj.addEventListener){
        obj.addEventListener(evt,fn,false);
    }else if(oTarget.attachEvent){
        obj.attachEvent("on" + evt,fn);
    }else{
        obj["on" + evt] = fn;
    }

}

20、元素添加on方法

Element.prototype.on = Element.prototype.addEventListener;

NodeList.prototype.on = function (event, fn) {、
    []['forEach'].call(this, function (el) {
        el.on(event, fn);
    });
    return this;
};

转自慕课网 ，原文链接http://www.imooc.com/article/7917