Search A String For Decimals.

this function is supposed to search a string for decimals and tell me how many of them it has found, but for some reason, it's not doing it right. since the "period" character is a special character in regular expressions,I went ahead and escaped it, but it's still doesn't work.

function ImprovedFormatAmount(ElementId)
{
var oElement = document.getElementById(ElementId);
var ElementValue = oElement.value;
var DecimalRegXp = /./g;
var OutputValue = ElementValue;
if (OutputValue.length > 0)
{alert (OutputValue.search(DecimalRegXp));}
}