javascript 常用函数

function number_format (number, decimals, dec_point, thousands_sep) {
// http://kevin.vanzonneveld.net // +   original by: Jonas Raoni Soares Silva (http://www.jsfromhell.com)
// +   improved by: Kevin van Zonneveld (http://kevin.vanzonneveld.net)
// +     bugfix by: Michael White (http://getsprink.com)
// +     bugfix by: Benjamin Lupton
// +     bugfix by: Allan Jensen (http://www.winternet.no)
// +    revised by: Jonas Raoni Soares Silva (http://www.jsfromhell.com)
// +     bugfix by: Howard Yeend
// +    revised by: Luke Smith (http://lucassmith.name)
// +     bugfix by: Diogo Resende
// +     bugfix by: Rival
// +      input by: Kheang Hok Chin (http://www.distantia.ca/)
// +   improved by: davook
// +   improved by: Brett Zamir (http://brett-zamir.me)
// +      input by: Jay Klehr
// +   improved by: Brett Zamir (http://brett-zamir.me)
// +      input by: Amir Habibi (http://www.residence-mixte.com/)
// +     bugfix by: Brett Zamir (http://brett-zamir.me)
// +   improved by: Theriault
// +      input by: Amirouche
// +   improved by: Kevin van Zonneveld (http://kevin.vanzonneveld.net)
// *     example 1: number_format(1234.56);
// *     returns 1: '1,235'
// *     example 2: number_format(1234.56, 2, ',', ' ');
// *     returns 2: '1 234,56'
// *     example 3: number_format(1234.5678, 2, '.', '');
// *     returns 3: '1234.57'
// *     example 4: number_format(67, 2, ',', '.');
// *     returns 4: '67,00'
// *     example 5: number_format(1000);
// *     returns 5: '1,000'
// *     example 6: number_format(67.311, 2);
// *     returns 6: '67.31'
// *     example 7: number_format(1000.55, 1);
// *     returns 7: '1,000.6'
// *     example 8: number_format(67000, 5, ',', '.');
// *     returns 8: '67.000,00000'
// *     example 9: number_format(0.9, 0);
// *     returns 9: '1'
// *    example 10: number_format('1.20', 2);
// *    returns 10: '1.20'
// *    example 11: number_format('1.20', 4);
// *    returns 11: '1.2000'
// *    example 12: number_format('1.2000', 3);
// *    returns 12: '1.200'
// *    example 13: number_format('1 000,50', 2, '.', ' ');
// *    returns 13: '100 050.00'
// Strip all characters but numerical ones.
number = (number + '').replace(/[^0-9+\-Ee.]/g, '');
var n = !isFinite(+number) ? 0 : +number,
prec = !isFinite(+decimals) ? 0 : Math.abs(decimals),
sep = (typeof thousands_sep === 'undefined') ? ',' : thousands_sep,
dec = (typeof dec_point === 'undefined') ? '.' : dec_point,
s = '',
toFixedFix = function (n, prec) {
var k = Math.pow(10, prec);
return '' + Math.round(n * k) / k;
};
// Fix for IE parseFloat(0.55).toFixed(0) = 0;
s = (prec ? toFixedFix(n, prec) : '' + Math.round(n)).split('.');
if (s[0].length > 3) {
s[0] = s[0].replace(/\B(?=(?:\d{3})+(?!\d))/g, sep);
}
if ((s[1] || '').length < prec) {
s[1] = s[1] || '';
s[1] += new Array(prec - s[1].length + 1).join('0');
}
return s.join(dec);
}

/*
　　　　 * number 传过来的值(保留两位小数)
* 如果有其他要求，可做适当修改
*/
　　　　function covertNumber(number)
{
　　　　　　　var temp = number.split('.');
var beforeLen = temp[0].length;
if (beforeLen > 3)
{
if (temp[0].substr(3,1) > 4)
{
var pointVal = temp[0].substr(1,1) + (parseInt(temp[0].substr(2,1))+1);
} else {
var pointVal = temp[0].substr(1,2);
}
} else {
var pointVal = temp[0].substr(1,2);
}
var powNumber = beforeLen-1 > 10 ? beforeLen-1 : '0'+beforeLen-1;

　　　　　　　return  temp[0].substr(0,1) + '.' + pointVal + 'E' + powNumber;

}

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