JS 日期转换，格式化等常用的函数定义

//判断字符串是否日期格式
function isDate(val) {
return new Date(val) != "Invalid Date";
}
//日期格式化
function formatDate2(val) {
return formatDate(val, 'yyyy-MM-dd');
}
//日期格式化
function formatDateTime(val) {
return formatDate(val, 'yyyy-MM-dd hh:mm:ss');
}
//数字格式化
function formatNumber(val) {
if (val != '') {
val = val.toFixed();
}
return formatWithThousandsSeparator(val);
}
//数字格式化
function formatNumber2(val) {
if (val != '') {
val = val.toFixed();
}
return formatWithThousandsSeparator(val);
}
//数字格式化
function formatNumber4(val) {
if (val != '') {
val = val.toFixed();
}
return formatWithThousandsSeparator(val);
}function formatDate(datestring, formatstring) {
if (formatstring == undefined) {
formatstring = 'yyyy-MM-dd';
} if (datestring == null || datestring == '/Date(-62135596800000)/' || datestring.length <= ) {
return '';
}
else {
var dateint = parseInt(datestring.substr());
return (new Date(dateint)).format(formatstring);
}
}//将数字转换成带千位分隔符
function formatWithThousandsSeparator(s) {
if (/[^-\.]/.test(s)) return s;
try {
s = String(s);
s = s.replace(/^(\d*)$/, "$1.");
s = (s + "&end").replace(/(\d*\.\d*)\d*/, "$1");
s = s.replace(".", ",");
var re = /(\d)(\d{},)/;
while (re.test(s))
s = s.replace(re, "$1,$2"); s = s.replace(/,(\d*)&end$/, ".$1"); if (s.substring(s.length - , s.length) == '.')
s = s.substring(, s.length - );
} catch (e)
{ }
return s;
}