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21.如何將日期對象設定為 5 天后的日期?
var myDate=new Date()
myDate.setDate(myDate.getDate()+5)
注意：如果增加天數會改變月份或者年份，那麼日期對象會自動完成這種轉換.
22.如何使用 sort() 方法從數值上對數組進行排序?
<html>
<body>
<script type="text/javascript">
function sortNumber(a, b)
{
return a - b
}
var arr = new Array(6)
arr[0] = "10"
arr[1] = "5"
arr[2] = "40"
arr[3] = "25"
arr[4] = "1000"
arr[5] = "1"
document.write(arr + "<br />")
document.write(arr.sort(sortNumber))
</script>
</body>
</html>
運行結果如下:
10,5,40,25,1000,1
1,5,10,25,40,1000
如果將arr.sort(sortNumber)中的sortNumber去掉,則結果為:
10,5,40,25,1000,1
1,10,1000,25,40,5
因為sort() 方法只從字面上對數組進行排序.
23.js動態產生控制項
HTML程式碼範例:
<html xmlns="http://www.w3.org/1999/xhtml" >
<head runat="server">
<title>無標題頁</title>
<script type="text/javascript">
function add()
{
var target=document.getElementById("span1");
var txt =document.getElementById("txt1");
var nCount=parseInt(txt.value);
nCount=nCount+1;
txt.value=nCount;
target.innerHTML=target.innerHTML+"<select id='select1'><option value='1'>1</option></select><br /><br />";
}
</script>
</head>
<body>
<form id="form1" runat="server">
<div>
<input type="button" value="添加" onclick="add()" /><input type="text" id="txt1" value="0" /><br />
<span id="span1"></span>
</div>
</form>
</body>
</html>
24.JS實現C#中Trim()函數功能
function ltrim(str)
{
var position;
position=str.length
for (i=0;i<str.length;i++)
{
if (str.charAt(i)!=" ")
{position=i;break;}
}
return (str.substring(position,str.length))
}
function rtrim(str)
{
var position
position=str.length
for (i=str.length-1;i>=0;i--)
{if (str.charAt(i)!=" ") {position=i;break;}}
return(str.substring(0,position+1))
}
//去除左右邊空格
function trim(str)
{return ltrim(rtrim(str))}
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