JavaScript学习总结（9）——JS常用函数（一）

2023-01-05 18:20:01

本文中，收集了一些比较常用的Javascript函数，希望对学习JS的朋友们有所帮助。

1. 字符串长度截取

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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

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

this.replace(new

RegExp(s1, "gm"),
s2)
}

3. 清除空格

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String.prototype.trim
= function()
{
    var

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

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

4. 清除左空格/右空格

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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

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String.prototype.startWith
= function

(s) {
    return

this.indexOf(s)
== 0
}

6. 判断是否以某个字符串结束

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String.prototype.endWith
= function

(s) {
    var

d = this.length
- s.length;
    return

(d >= 0 && this.lastIndexOf(s)
== d)
}

7. 转义html标签

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function

HtmlEncode(text) {
    return

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

8. 时间日期格式转换

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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

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function

isDigit(value) {
    var

patrn = /^[0-9]*$/;
    if

(patrn.exec(value) == null

|| value == "")
{
        return

false
    }
else

{
        return

true
    }
}

10. 设置cookie值

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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;"
}

11. 获取cookie值

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function

getCookie(name) {
    var

arr = document.cookie.match(new

RegExp("(^|
)"
+ name + "=([^;]*)(;|$)"));
    if

(arr != null)
return

unescape(arr[2]);
    return

null
}

12. 加入收藏夹

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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")
        }
    }
}

13. 设为首页

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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')
    }
}

14. 加载样式文件

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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)
    }
}

15. 返回脚本内容

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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;
}

16. 清除脚本内容

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function

stripscript(s) {
    return

s.replace(/<script.*?>.*?<\/script>/ig, '');
}

17. 动态加载脚本文件

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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)
{}
}

18. 返回按ID检索的元素对象

function $(id) {

    return !id ? null : document.getElementById(id);

}

19. 跨浏览器绑定事件

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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;
    }
}

20. 跨浏览器删除事件

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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;
    }
}

21. 为元素添加on方法

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Element.prototype.on
= Element.prototype.addEventListener;
  
NodeList.prototype.on
= function

(event, fn) {、
    []['forEach'].call(this,
function

(el) {
        el.on(event,
fn);
    });
    return

this;
};

22. 为元素添加trigger方法

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Element.prototype.trigger
= function

(type, data) {
    var

event = document.createEvent('HTMLEvents');
    event.initEvent(type,
true,
true);
    event.data
= data || {};
    event.eventName
= type;
    event.target
= this;
    this.dispatchEvent(event);
    return

this;
};
NodeList.prototype.trigger
= function

(event) {
    []['forEach'].call(this,
function

(el) {
        el['trigger'](event);
    });
    return

this;
};

23. 检验URL链接是否有效

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function

getUrlState(URL){
    var

xmlhttp = new

ActiveXObject("microsoft.xmlhttp");
    xmlhttp.Open("GET",URL,
false); 
    try{ 
            xmlhttp.Send();
    }catch(e){
    }finally{
        var

result = xmlhttp.responseText;
        if(result){
            if(xmlhttp.Status==200){
                return(true);
             }else{
                   return(false);
             }
         }else{
             return(false);
         }
    }
}

24. 格式化CSS样式代码

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function

formatCss(s){//格式化代码
    s
= s.replace(/\s*([\{\}\:\;\,])\s*/g, "$1");
    s
= s.replace(/;\s*;/g, ";");
//清除连续分号
    s
= s.replace(/\,[\s\.\#\d]*{/g,
"{");
    s
= s.replace(/([^\s])\{([^\s])/g, "$1
{\n\t$2");
    s
= s.replace(/([^\s])\}([^\n]*)/g, "$1\n}\n$2");
    s
= s.replace(/([^\s]);([^\s\}])/g, "$1;\n\t$2");
    return

s;
}

25. 压缩CSS样式代码

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function

compressCss (s) {//压缩代码
    s
= s.replace(/\/\*(.|\n)*?\*\//g,
""); //删除注释
    s
= s.replace(/\s*([\{\}\:\;\,])\s*/g, "$1");
    s
= s.replace(/\,[\s\.\#\d]*\{/g,
"{"); //容错处理
    s
= s.replace(/;\s*;/g, ";");
//清除连续分号
    s
= s.match(/^\s*(\S+(\s+\S+)*)\s*$/); //去掉首尾空白
    return

(s == null)
? ""

: s[1];
}

26. 获取当前路径

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var

currentPageUrl = "";
if

(typeof

this.href
=== "undefined")
{
    currentPageUrl
= document.location.toString().toLowerCase();
}else

{
    currentPageUrl
= this.href.toString().toLowerCase();
}

27. 判断是否移动设备

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function

isMobile(){
    if

(typeof

this._isMobile
=== 'boolean'){
        return

this._isMobile;
    }
    var

screenWidth = this.getScreenWidth();
    var

fixViewPortsExperiment = rendererModel.runningExperiments.FixViewport ||rendererModel.runningExperiments.fixviewport;
    var

fixViewPortsExperimentRunning = fixViewPortsExperiment && (fixViewPortsExperiment.toLowerCase() ===
"new");
    if(!fixViewPortsExperiment){
        if(!this.isAppleMobileDevice()){
            screenWidth
= screenWidth/window.devicePixelRatio;
        }
    }
    var

isMobileScreenSize = screenWidth < 600;
    var

isMobileUserAgent = false;
    this._isMobile
= isMobileScreenSize && this.isTouchScreen();
    return

this._isMobile;
}

28. 判断是否移动设备访问

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function

isMobileUserAgent(){
    return

(/iphone|ipod|android.*mobile|windows.*phone|blackberry.*mobile/i.test(window.navigator.userAgent.toLowerCase()));
}

29. 判断是否苹果移动设备访问

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function

isAppleMobileDevice(){
    return

(/iphone|ipod|ipad|Macintosh/i.test(navigator.userAgent.toLowerCase()));
}

30. 判断是否安卓移动设备访问

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function

isAndroidMobileDevice(){
    return

(/android/i.test(navigator.userAgent.toLowerCase()));
}

31. 判断是否Touch屏幕

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function

isTouchScreen(){
    return

(('ontouchstart'

in
window) || window.DocumentTouch && document instanceof

DocumentTouch);
}

32. 判断是否打开视窗

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function

isViewportOpen() {
    return

!!document.getElementById('wixMobileViewport');
}

33. 获取移动设备初始化大小

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function

getInitZoom(){
    if(!this._initZoom){
        var

screenWidth = Math.min(screen.height, screen.width);
        if(this.isAndroidMobileDevice()
&& !this.isNewChromeOnAndroid()){
            screenWidth
= screenWidth/window.devicePixelRatio;
        }
            this._initZoom
= screenWidth /document.body.offsetWidth;
        }
    return

this._initZoom;
}

34. 获取移动设备最大化大小

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function

getZoom(){
    var

screenWidth = (Math.abs(window.orientation) === 90) ? Math.max(screen.height, screen.width) : Math.min(screen.height, screen.width);
    if(this.isAndroidMobileDevice()
&& !this.isNewChromeOnAndroid()){
        screenWidth
= screenWidth/window.devicePixelRatio;
    }
    var

FixViewPortsExperiment = rendererModel.runningExperiments.FixViewport || rendererModel.runningExperiments.fixviewport;
    var

FixViewPortsExperimentRunning = FixViewPortsExperiment && (FixViewPortsExperiment ===
"New"

|| FixViewPortsExperiment === "new");
    if(FixViewPortsExperimentRunning){
        return

screenWidth / window.innerWidth;
    }else{
        return

screenWidth / document.body.offsetWidth;
    }
}

35. 获取移动设备屏幕宽度

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function

getScreenWidth(){
    var

smallerSide = Math.min(screen.width, screen.height);
    var

fixViewPortsExperiment = rendererModel.runningExperiments.FixViewport || rendererModel.runningExperiments.fixviewport;
    var

fixViewPortsExperimentRunning = fixViewPortsExperiment && (fixViewPortsExperiment.toLowerCase() ===
"new");
    if(fixViewPortsExperiment){
        if(this.isAndroidMobileDevice()
&& !this.isNewChromeOnAndroid()){
            smallerSide
= smallerSide/window.devicePixelRatio;
        }
    }
    return

smallerSide;
}

36. 完美判断是否为网址

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function

IsURL(strUrl) {
    var

regular = /^\b(((https?|ftp):\/\/)?[-a-z0-9]+(\.[-a-z0-9]+)*\.(?:com|edu|gov|int|mil|net|org|biz|info|name|museum|asia|coop|aero|[a-z][a-z]|((25[0-5])|(2[0-4]\d)|(1\d\d)|([1-9]\d)|\d))\b(\/[-a-z0-9_:\@&?=+,.!\/~%\$]*)?)$/i
    if

(regular.test(strUrl)) {
        return

true;
    }else

{
        return

false;
    }
}
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