有用的js 代码

http://chinapkw.iteye.com/blog/125612

 

 

1.每一项都是js中的小技巧，但十分的实用！   

            略. http://chinapkw.iteye.com/blog/125612

2.+++++++++++++++++++++++++++++++++++++++++++++++

程序代码
//去左空格;
function
 ltrim(s){
return
 s.replace( /^\s*/, 
""
);
}
 程序代码
//去右空格;
function
 rtrim(s){
return
 s.replace( /\s*$/, 
""
);
}
 程序代码
//左右空格;
function
 trim(s){
return
 rtrim(ltrim(s));
}
 程序代码
//替换
function
 replace(s, t, u) {
i = s.indexOf(t);
r = 
""
;
if
 (i == -1) 
return
 s;
r += s.substring(0,i) + u;
if
 ( i + t.length < s.length)
r += replace(s.substring(i + t.length, s.length), t, u);
return
 r;
}
 程序代码
//检查非法字符
//str 要检查的字符
//badwords 非法字符 &|<>=
function
 checkbadwords(str, badwords) {
if
 (
typeof
 (str) != 
"string"
 || 
typeof
 (badwords) != 
"string"
) {
return
 (
false
);
}
for
 (i=0; i<badwords.length; i++) {
bad = badwords.charAt(i);
for
 (j=0; j<str.length; j++) {
if
 (bad == str.charAt(j)) {
return
 
false
;
break
;
}
}
}
return
 
true
;
}
 程序代码
//检查合法字符,限制只能输入的字符
//str 要检查的字符
//goodwords 合法字符 1234567890abcdefghijklmnopqrstuvwxyz
function
 checkgoodwords(str, goodwords) {
if
 (
typeof
 (str) != 
"string"
 || 
typeof
 (goodwords) != 
"string"
) {
return
 (
false
);
}
for
 (i=0; i<str.length; i++) {
this_str = str.charAt(i);
for
 (j=0; j<goodwords.length; j++) {
if
 (this_str == goodwords.charAt(j)) {
break
;
}
if
(j==goodwords.length-1){
return
 
false
;
}
}
}
return
 
true
;
}
 程序代码
//函 数 名：chkinteger
//功能介绍：检查是否为数字
//参数说明：要检查的字符串
//返 回 值：false:不是 true:是
function
 chkinteger(checkStr) {
var
 checkOK = 
"0123456789+-"
;
var
 allValid = 
true
;
for
 (i=0; i<checkStr.length; i++) {
ch = checkStr.charAt(i);
if
 (checkOK.indexOf(ch) == -1) {
allValid = 
false
;
break
;
}
if
 ((ch == '+' || ch == '-') && i>0) {
allValid = 
false
;
break
;
}
}
return
 (allValid);
}
 程序代码
//函 数 名：chklength
//功能介绍：检查字符串的长度
//参数说明：要检查的字符串
//返 回 值：字节长度值
function
 chklength(checkStr) {
var
 n = 0;
for
 (i=0; i<checkStr.length; i++) {
chcode = checkStr.charCodeAt(i);
if
 (chcode>=0 && chcode<=255) {
n++;
} 
else
 {
n += 2;
}
}
return
 (n);
}
 程序代码
//复选框全选和不全选
//使用方法：
//<input name="chkAll" type="checkbox" id="chkAll" onclick=CheckAll(this.form) value="checkbox">
function
 unselectall()
{
if
(document.myform.chkAll.checked){
document.myform.chkAll.checked = document.myform.chkAll.checked&0;
}
}
function
 CheckAll(form)
{
for
 (
var
 i=0;i<form.elements.length;i++)
{
var
 e = form.elements[i];
if
 (e.Name != 
"chkAll"
&&e.disabled==
false
)
e.checked = form.chkAll.checked;
}
}
 程序代码
//check date
//return: 1,days 2,false
//2005-12-19 2005-12-29
function
 checkdate(start_date,end_date){
//alert("start_date:["+start_date+"] end_date:["+end_date+"]");
//isnull
if
(start_date==
""
 || end_date==
""
){
//alert("false");
return
 
false
;
}
var
 strSeparator = 
"-"
; 
//split symbol
//is-
if
(start_date.charAt(4)!=strSeparator && start_date.charAt(7)!=strSeparator && end_date.charAt(4)!=strSeparator && end_date.charAt(7)!=strSeparator){
//alert(start_date.charAt(7));
return
 
false
;
}
var
 strDateArrayStart;
var
 strDateArrayEnd;
strDateArrayStart = start_date.split(strSeparator);
strDateArrayEnd = end_date.split(strSeparator);
var
 strDateS = 
new
 Date(strDateArrayStart[0] + 
"/"
 + strDateArrayStart[1] + 
"/"
 + strDateArrayStart[2]);
var
 strDateE = 
new
 Date(strDateArrayEnd[0] + 
"/"
 + strDateArrayEnd[1] + 
"/"
 + strDateArrayEnd[2]);
//check date
var
 intDay;
intDay = (strDateE-strDateS)/(1000*3600*24);
//alert(intDay);
return
 intDay;
}
 程序代码
//checkdate_month
//return: 1,true 2,false
//2005-12-19 2005-12-29
//month: number
function
 checkdate_month(start_date,end_date,month){
//alert("start_date:["+start_date+"] end_date:["+end_date+"]");
//isnull
if
(start_date==
""
 || end_date==
""
 || month==
""
){
//alert("false");
return
 
false
;
}
var
 strSeparator = 
"-"
; 
//split symbol
//is-
if
(start_date.charAt(4)!=strSeparator && start_date.charAt(7)!=strSeparator && end_date.charAt(4)!=strSeparator && end_date.charAt(7)!=strSeparator){
//alert(start_date.charAt(7));
return
 
false
;
}
var
 strDateArrayStart;
var
 strDateArrayEnd;
strDateArrayStart = start_date.split(strSeparator);
strDateArrayEnd = end_date.split(strSeparator);
var
 strDateS = 
new
 Date(strDateArrayStart[0] + 
"/"
 + strDateArrayStart[1] + 
"/"
 + strDateArrayStart[2]);
var
 strDateE = 
new
 Date(strDateArrayEnd[0] + 
"/"
 + strDateArrayEnd[1] + 
"/"
 + strDateArrayEnd[2]);
//check date
var
 intDay;
intDay = (strDateE-strDateS)/(1000*3600*24);
//alert(intDay);
var
 intMonth = intDay/30;
if
(intMonth>month){
return
 
false
;
}
return
 
true
;
}