20个最常用的javascript方法函数

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 + "..."
}

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;"
}

11
获取cookie值

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

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

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

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

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

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

17
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) {}
}

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

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

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;
}
}