A JavaScript function to format a number into a string.

formatNumber.func.js

function formatNumber(v, format){
  if(format.indexOf(".")>-1){
    var neg = false;
    if(v<0)neg = true;
    v = Math.abs(v);
    var bd = format.indexOf(".");
    var ad = format.length-bd-1;
    var b = Math.floor(v);
    var a = v - b;
    b+="";
    while(b.length < bd)
      b="0"+b;
    if(a==0){
      a = "";
      while(a.length < ad)
        a+="0";
    } else {
      a = Math.round(a*Math.pow(10, ad));
    }
    if(neg)
      return "-"+b+"."+a;
    else 
      return b+"."+a;
  } else {
    var bd = format.length;
    b=Math.round(v)+"";
    while(b.length < bd)
      b="0"+b;
    return b;
  }
};

formatNumber.func.min.js

function formatNumber(a,b){if(b.indexOf(".")>-1){var c=!1;a<0&&(c=!0),a=Math.abs(a);var d=b.indexOf("."),e=b.length-d-1,f=Math.floor(a),g=a-f;for(f+="";f.length<d;)f="0"+f;if(0==g)for(g="";g.length<e;)g+="0";else g=Math.round(g*Math.pow(10,e));return c?"-"+f+"."+g:f+"."+g}var d=b.length;for(f=Math.round(a)+"";f.length<d;)f="0"+f;return f};