function trim(str)
{
    if (str != null && str != "") 
    {
        while (str.indexOf(' ') == 0 )
        {
            str = str.substring(1);
            if (str==null||str=="") 
            {
                break;
            }
        }
        while (str.lastIndexOf(' ') == str.length-1) 
        {
            str = str.substring(0,str.length-1);
            if (str == null || str == "" ) 
                break;
        }
    }
    return str;
}


function select_All(formname,checkboxname)
{            //全选//
    var length=formname.length;         //formname如document.form1   checkboxname如document.form1.checkbox//              
    var flag=checkboxname.checked;
    for (i=0;i<length;i++)
    {
        if(formname.elements[i].type!="checkbox") continue;
        formname.elements[i].checked = flag;
    }
}

function isSelectedAll(formName)
{
    for (i = 0;i < formName.length;i++)
    {
        if(formName.elements[i].type!="checkbox") continue;
        if (formName.elements[i].checked == false)
            return false;
    }
    return true;
}

function checkDate(dateValue)
{
    var nen=0;
    var tuki=0;
    var hi=0;
    if ( dateValue.length != 10 )
    {
        return false;
    }

    var moji = new Array(5);
    moji[0]= dateValue.substring(0, 4);
    moji[1]= dateValue.substring(5, 7);
    moji[2]= dateValue.substring(8, 10);
    moji[3] = dateValue.charAt(4);
    moji[4] = dateValue.charAt(7);
    if (moji[3] != "-" || moji[4] != "-")
        return false;
    if (( isNaN(moji[0]) == true ) ||
        ( isNaN(moji[1]) == true ) ||
        ( isNaN(moji[2]) == true ))
    {
        return false;
    }
    
    nen  = eval(moji[0]);
    tuki = eval(moji[1]);
    hi   = eval(moji[2]);


    if (( nen < 0001 ) ||
        ( nen > 9999 )) {
        return false;
    }
    if (( tuki < 1 ) ||
        ( tuki > 12 )) {
        return false;
    }
    if ( hi < 1) {
        return false;
    }

    if (( tuki == 1 ) ||
        ( tuki == 3 ) ||
        ( tuki == 5 ) ||
        ( tuki == 7 ) ||
        ( tuki == 8 ) ||
        ( tuki == 10) ||
        ( tuki == 12)) 
    {
        if ( hi > 31 ) 
        {
            return false;
        }
    }

    if (( tuki == 4 ) ||
        ( tuki == 6 ) ||
        ( tuki == 9 ) ||
        ( tuki == 11)) 
    {
        if ( hi > 30 ) 
        {
            return false;
        }
    }

    if ( tuki == 2 )
    {
        if ( (nen%400) == 0 ) 
        {
            if ( hi > 29 ) 
            {
                return false;
            }
        } 
        else 
        {
            if ( (nen%100) == 0 ) 
            {
                if ( hi > 28 ) 
                {
                    return false;
                }
            } else 
            {
                if ( (nen%4) == 0 ) 
                {
                    if ( hi > 29 ) 
                    {
                        return false;
                    }
                } 
                else 
                {
                    if ( hi > 28 ) 
                    {
                        return false;
                    }
                }
            }
        }
    }
    return true;
}

function checkYearElement(element)
{
  var year=element.value;
  if (trim(year) == "" )
  {
    alert("请输入年份！");
    return false;
  } 
  if (isNaN(year))
  {
    alert("请输入合法的年份! 年份必须是数字！");
    element.select();
    return false
  }
  if(year<1930 || year>2050) 
  {
     alert("年份必须在1930与2050之间");
     element.select();
     return false;
  }
  return true
}
//检查某个Form里面的选择框是否选中，formName是form对象，selectType是选择框的类型，就checkbox和radio
function checkChoice(formName,selectType)
{
    var length = formName.length;
    for (i = 0;i < length ;i++)
    {
        if(formName.elements[i].type != selectType) continue;
        if(formName.elements[i].checked == true)  return true;
    }
    return false;
}
//检查一个Form里是否由checkbox选中，selectAllName是全选框
function checkOutCheckBox(formName,selectAllName)
{
    var length = formName.length;
    for (i = 0;i < length ;i++)
    {
        if(formName.elements[i].type != "checkbox") continue;
        if(formName.elements[i].name == selectAllName) continue;
        if(formName.elements[i].checked == true)  return true;
    }
    return false;
}

function select_Group(formName,srcName,objName)
{
    var flag = srcName.checked;
    for(i =0 ; i < document.forms[0].length; i++)
    {
        if (formName.elements[i].type != "checkbox") continue;
        if (formName.elements[i].name != objName) continue;
        formName.elements[i].checked = flag;
    }
}

function checkAddress(str){
	if(checkIsInteger(str))
 		if(str >= 0 &&  str < 256)
 		 return true;
 	return false;
 		 
}



function checkIsInteger(str)
{
    //如果为空，则不能通过校验
    if(str == "")
        return false;
    if(/^(\-?)(\d+)$/.test(str))
        return true;
    else
        return false;
}

function checkBoxGroup(form,groupName)
{
    var length = form.length;
    for (i = 0;i < length ;i++)
    {
        if(form.elements[i].type != "checkbox") continue;
        if(form.elements[i].name != groupName) continue;
        if(form.elements[i].checked == true)  return true;
    }
    return false;
}


function checkPositive(str)
{
	var digits = "0123456789";
	for (i = 0; i < str.length; i++)
	{
		var c = str.charAt(i);
		if (digits.indexOf(c) == -1)
			return false;
	}
	var num = parseInt(str);
	if(isNaN(num) || num <= 0)
		return false;
	return true;
}