function str_replace (search, replace, subject, count) {
    // Replaces all occurrences of search in haystack with replace  
    // version: 1004.1212
    // discuss at: http://phpjs.org/functions/str_replace    // +   original by: Kevin van Zonneveld (http://kevin.vanzonneveld.net)

    // *     example 1: str_replace(' ', '.', 'Kevin van Zonneveld');
    // *     returns 1: 'Kevin.van.Zonneveld'
    // *     example 2: str_replace(['{name}', 'l'], ['hello', 'm'], '{name}, lars');
    // *     returns 2: 'hemmo, mars'    var i = 0, j = 0, temp = '', repl = '', sl = 0, fl = 0,
            f = [].concat(search),
            r = [].concat(replace),
            s = subject,
            ra = r instanceof Array, sa = s instanceof Array;    s = [].concat(s);
    if (count) {
        this.window[count] = 0;
    }
     for (i=0, sl=s.length; i < sl; i++) {
        if (s[i] === '') {
            continue;
        }
        for (j=0, fl=f.length; j < fl; j++) {            temp = s[i]+'';
            repl = ra ? (r[j] !== undefined ? r[j] : '') : r[0];
            s[i] = (temp).split(f[j]).join(repl);
            if (count && s[i] !== temp) {
                this.window[count] += (temp.length-s[i].length)/f[j].length;}        }
    }
    return sa ? s : s[0];
}

function is_numeric(input){
	input = str_replace(',', '.', input)
	var pattern =  /^-?(0|[1-9]\d*|(?=\.))(\.\d+)?$/;
	//var pattern = /^-{0,1}\d*\.{0,1}\d+$/;
	return (pattern.test(input));
}