JavaScript学习总结（9）——JS常用函数（一）
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 +
"..."
}
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2. 替换全部
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String.prototype.replaceAll =
function
(s1, s2) {
return
this
.replace(
new
RegExp(s1,
"gm"
), s2)
}
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3. 清除空格
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String.prototype.trim =
function
() {
var
reExtraSpace = /^\s*(.*?)\s+$/;
return
this
.replace(reExtraSpace,
"$1"
)
}
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4. 清除左空格/右空格
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function
ltrim(s){
return
s.replace( /^(\s*| *)/,
""
); }
function
rtrim(s){
return
s.replace( /(\s*| *)$/,
""
); }
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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
}
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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)
}
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7. 转义html标签
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function
HtmlEncode(text) {
return
text.replace(/&/g,
'&'
).replace(/\
"/g, '"
').replace(/</g,
'<'
).replace(/>/g,
'>'
)
}
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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
}
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9. 判断是否为数字类型
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function
isDigit(value) {
var
patrn = /^[0-9]*$/;
if
(patrn.exec(value) ==
null
|| value ==
""
) {
return
false
}
else
{
return
true
}
}
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10. 设置cookie值
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function
setCookie(name, value, Hours) {
var
d =
new
Date();
var
offset = 8;
var
utc = d.getTime() + (d.getTimezoneOffset() * 60000);
var
nd = utc + (3600000 * offset);
var
exp =
new
Date(nd);
exp.setTime(exp.getTime() + Hours * 60 * 60 * 1000);
document.cookie = name +
"="
+ escape(value) +
";path=/;expires="
+ exp.toGMTString() +
";domain=360doc.com;"
}
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11. 获取cookie值
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function
getCookie(name) {
var
arr = document.cookie.match(
new
RegExp(
"(^| )"
+ name +
"=([^;]*)(;|$)"
));
if
(arr !=
null
)
return
unescape(arr[2]);
return
null
}
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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"
)
}
}
}
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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'
)
}
}
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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)
}
}
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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;
}
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16. 清除脚本内容
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function
stripscript(s) {
return
s.replace(/<script.*?>.*?<\/script>/ig,
''
);
}
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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) {}
}
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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;
}
}
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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;
}
}
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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
;
};
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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
;
};
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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
);
}
}
}
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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;
}
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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];
}
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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();
}
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27. 判断是否移动设备
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