js奇偶数判断的代码_javascript技巧

有两个变量 a 和 b 
如果a=1,3,5,7,9 则b="奇数"
如果a=2,4,6,8  则b="偶数"
如果a="0" 则b="零"

<script language="JavaScript" type="text/javascript"> <!-- function chk(num){ return num?num%2?"奇数":"偶数":"0" } function show(num){ if(num=="") {alert("没有填写数字!");return false;} if(isNaN(num)) {alert("非数字!");return false;} if(num>9){alert("大于9被强行改为1");alert(chk(1));}else if(num<0){alert("小于0被强行改为0");alert(chk(0));}else if(num==0){alert(chk(0));}else{alert(chk(num))} } //--> </script> <form name="abc"> <input name="num" id="num" type="text" value=""> <input name="chk" id="chk" type="button" value="检查" onclick="show(this.form.num.value)"> </form>
[Ctrl+A 全选 注:如需引入外部Js需刷新才能执行]