js如何获得下拉菜单改变前的值?
<select name='selectSS' onChange="GaiBian()"><option value='1'>1</option><option value='2'>2</option><option value='3'>3</option></select>
请问在GaiBian()这个方法里我应该怎么样获取改变前的值呀?或者用什么别的事件?
[解决办法]
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN"><html> <head> <script language="JavaScript"> <!-- function GaiBian(osel){ alert(osel.options[osel.selectedIndex].text); } //--> </script> </head> <body> <select name='selectSS' onChange="GaiBian(this)"> <option value='1'>1 </option> <option value='2'>2 </option> <option value='3'>3 </option> </select> </body></html>
[解决办法]
var $=function(Id){ return document.getElementById(Id)?document.getElementById(Id):Id;};var $N=function(Name){ return document.getElementsByName(Name)?document.getElementsByName(Name):Name;};//获取select的值var $S=function(Id){ return $(Id).options[$(Id).selectedIndex].value;}//获取radio的值var $R=function(name){ var radio = $N(name); var getresult = 0; for (var i=0;i<radio.length;i++){ if(radio[i].checked) getresult = radio[i].value; } return getresult;};//调用$S("select的id名")
[解决办法]
<html><body><script type="text/javascript">var prevVal = null;window.onload = saveSel;function $(id){ return document.getElementById(id);}function saveSel(){ prevVal = $("selectSS").options[$("selectSS").selectedIndex].value;}function GaiBian(){ if(prevVal != null){ alert("选择之前的值:"+prevVal); } saveSel(); alert("现在的值:" + prevVal);}</script><select name='selectSS' id="selectSS" onChange="GaiBian()"> <option value='1'>1 </option> <option value='2'>2 </option> <option value='3'>3 </option> </select> </body></html>
[解决办法]
3楼可行，保存上一项的值
[解决办法]
<script language="JavaScript">
<!--
function GaiBian(obj){
alert(obj.options[obj.selectedIndex].value);
}
//-->
</script>