常用js方法

//去左空格;
function ltrim(s){
return s.replace( /^/s*/, "");
}
//去右空格;
function rtrim(s){
return s.replace( //s*$/, "");
}
//左右空格;
function trim(s){
return rtrim(ltrim(s));
}
//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;
}
//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;
}
//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;
}
//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);
}
//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);
}
//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;
}
}
//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;
}
//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 ；

}