格式化输出数字

/******************************************************
*@param object
* 1.object可以为文本框的对象或文本框的Id
例如：<input type="text" name="text1" id="value1" value="20.1">
var elements = document.forms[0].elements;
formatNumber(elements["text1"],true);
formatNumber("value1",true);
* 2.object可以为层的Id
例如：<span id="value">20.1</span>
formatNumber(value,true);
formatNumber("value",true);
*@param isShowEmpty 如果对象的值为空，是否显示
*@param precision 显示的小数位数
*/
function formatNumber(object,isShowEmpty,precision){
if(typeof(object) == "string"){
object = document.getElementById(object);
}
if(typeof(object) == "undefined" || object == null){
alert("The object is not found!");
return;
}
var value = object.value;
var isFormObject = true;//是否为表单对象
if(typeof(value) == "undefined"){
value = object.innerText;
isFormObject = false;
}
if(value == ""){
return;
}
if(typeof(precision) == "undefined"){
precision = 2;
}
var number = parseFloat(value);
if(number <= 0 ){
if(isShowEmpty){
if(isFormObject){
object.value = "";
}else{
object.innerText = "";
}

}
else{
var str = "";
for(var i = 0; i < precision; i++){
str += "0";
}
if(isFormObject){
object.value = "0."+str;
}else{
object.innerText = "0." + str;
}
}
return;
}
if(isFormObject){
object.value = number.toFixed(precision);
}else{
object.innerText = number.toFixed(precision);
}
}