最常用的20个javascript方法函数

常用的`javascript方法函数有哪些?下面YJBYS小编为你盘点，废话不说，直接放码!

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, '>')

}

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;