请教高手:javascript怎么判断一个文本框获得了焦点?很急!!!!!!

<input type="text" onFocus="openKeyBoard">
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=gb2312">
<title>softkeyboard:code by meixx</title>
<script language="javascript">
var oPopUp=null;
function SoftKeyboard(pwdObj){
oPopUp=window.createPopup();
var popBody=oPopUp.document.body;
popBody.style.backgroundColor = "#FFFF99";
popBody.style.border = "solid black 1px";
WriteToPopup(oPopUp,pwdObj);
oPopUp.show(0,22,325,136,pwdObj);
}
function WriteToPopup(oPopUp,pwdObj){
var strHTML="<html><head>";
strHTML+='<meta http-equiv="Content-Type" content="text/html; charset=gb2312">';
strHTML+='<style type="text/css">';
strHTML+='.tdnormal{text-align:center; background-image:url(images/bz.GIF); font:13px; color:black; background-repeat:no-repeat; background-position:100% 100%}';
strHTML+='.tdover{text-align:center;  background-image:url(images/z.GIF);  font:13px; color:black}';
strHTML+='.tdclick{text-align:center; background-image:url(images/zz.GIF); font:13px; color:white}';
strHTML+='.button{border:0;width:90%; height:95%; }';
strHTML+='</style>';
strHTML+='<script language="javascript">';
strHTML+='var arrLow=new Array("`","1","2","3","4","5","6","7","8","9","0","-","=","\\\\","a","b","c","d","e","f","g","h","i","j","k","l","m","n","o","p","q","r","s","t","u","v","w","x","y","z","[","]",";","\'",",",".","/","");';
strHTML+='var arrUp =new Array("~","!","@","#","$","%","^","&","*","(",")","_","+","|","A","B","C","D","E","F","G","H","I","J","K","L","M","N","O","P","Q","R","S","T","U","V","W","X","Y","Z","{","}",":","\\"","<",">","?",""); ';
strHTML+='var curOverTd=null; var curClkTd=null; var CapsStatus="black";';
strHTML+='var pwdObjectId=parent.document.getElementById("'+pwdObj.id+'");';
strHTML+='function TdMouseOver(TdObj){ ';
strHTML+=' TdObj.className ="tdover"; ';
strHTML+=' curOverTd=TdObj;} ';
strHTML+='function TdMouseOut(TdObj){ ';
strHTML+=' if(curClkTd==TdObj)';
strHTML+=' TdObj.className ="tdclick"; ';
strHTML+=' else';
strHTML+=' TdObj.className ="tdnormal"; ';
strHTML+=' } ';
strHTML+='function TdMouseClk(TdObj){ ';
strHTML+=' if(curClkTd)';
strHTML+=' curClkTd.className ="tdnormal"; ';
strHTML+=' TdObj.className ="tdclick"; ';
strHTML+=' curClkTd=TdObj; ';
strHTML+=' curOverTd=null; ';
strHTML+='  pwdObjectId.value+=TdObj.innerText;';
strHTML+=' }';
strHTML+=' function btnCapsDown(btnObj){';
strHTML+=' if(CapsStatus=="black"){ CapsStatus="green"; ChgText(arrUp);}';
strHTML+=' else{ CapsStatus="black"; ChgText(arrLow);}; ';
strHTML+=' btnObj.style.color=CapsStatus=="black"?"#000000":"#33FF66";';
strHTML+=' if(curClkTd){ if(curClkTd.className=="tdclick") curClkTd.className="tdnormal"; else curClkTd.className="tdclick"; }';
strHTML+=' btnObj.style.color=CapsStatus=="black"?"#000000":"#33FF66";';
strHTML+=' }';
strHTML+=' function ChgText(arr){';
strHTML+=' var table=document.getElementById("tbKeyboard");';
strHTML+=' for(var i=0;i<4;i++)';
strHTML+=' for(var j=0;j<12;j++)';
strHTML+=' table.rows[i].cells[j].innerText=arr[12*i+j];';
strHTML+=' }';
strHTML+=' function btnSpaceDown(){';
strHTML+=' pwdObjectId.value+=" "';
strHTML+=' }';
strHTML+=' function btnBackDown(){';
strHTML+=' pwdObjectId.value=pwdObjectId.value.substring(0,pwdObjectId.value.length-1)';
strHTML+=' }';
strHTML+=' function btnEnterDown(){';
strHTML+=' parent.oPopUp.hide();';
strHTML+=' }';
strHTML+='</scr'+'ipt></head> ';
strHTML+='<body bgcolor="#FFFFFF" style="margin:2; border:1 solid #3C97C6;overflow:hidden;" oncontextmenu="javascript:event.returnValue=false;" onselectstart="javascript:event.returnValue=false;"> ';
strHTML+='<table id="tbKeyboard" cellpadding="0" cellspacing="0" border="1" style="TABLE-LAYOUT: fixed; width:100%;height:100%; border-collapse:collapse; cursor:default" bordercolor="#FFFFFF">';
var arr=new Array("`","1","2","3","4","5","6","7","8","9","0","-","=","\\","a","b","c","d","e","f","g","h","i","j","k","l","m","n","o","p","q","r","s","t","u","v","w","x","y","z","[","]",";","\'",",",".","/","");
for(var i=0;i<4;i++){
strHTML+='<tr height="27">';
for(var j=0;j<12;j++)
strHTML+='<td class="tdnormal" valign="middle" onMouseOver="TdMouseOver(this)" onMouseOut="TdMouseOut(this)" onClick="TdMouseClk(this)">'+arr[i*12+j]+'</td>';
strHTML+='</tr">';
}
strHTML+='<tr height=""><td class="tdnormal" colspan="12"><table width="100%"  border="0" cellpadding="0" cellspacing="0" style="margin:0">';
strHTML+='<tr><td class="tdnormal" width="20%" valign="middle"><input type="button" value="Shift" style="font-weight:800 " onclick="btnCapsDown(this)" class="button"></td>';
strHTML+='<td class="tdnormal" width="35%" valign="middle"><input type="button" value="Space" onclick="btnSpaceDown()" class="button"></td>';
strHTML+='<td class="tdnormal" width="25%" valign="middle"><input type="button" value="Back" onclick="btnBackDown()" class="button"></td>';
strHTML+='<td class="tdnormal" width="20%" valign="middle"><input type="button" value="Enter" onclick="btnEnterDown()" class="button"></td>';
strHTML+='</tr></table></td>';
strHTML+='</tr></table></body></html>';
oPopUp.document.write(strHTML);
}
</script>
</head><body onload="javascript:txtPwd.click()">
<input type="text" id="txtPwd" name="txtPwd" onclick="SoftKeyboard(this)" readonly="readonly">
</body>
</html>

解决方案 »

  1.   

    document.activeElement    得到当前网页中得到焦点的控件你可以判断网页里得到焦点的控件的ID是不是你指定的控件的ID:
    if(document.activeElement.id == "yourId")
    {
    }
      

  2.   

    zhaoxiaoyang(梅雪香@hisoft)的代码,有问题出错,如果点击出现运行错误,openKeyBord未定义
    判断了焦点在控件上,怎么传按钮的值到文本框,一点按钮,焦点就变化了,因为这是放在触摸屏上（用的是页面上做的数字键盘输入的不是键盘），不是在桌面电脑上 ,怎么办?
      

  3.   

    zhaoxiaoyang(梅雪香@hisoft)的代码第一行改一改:<input type="text" onFocus="SoftKeyboard(this)">
      

  4.   

    sorry, 再改<input type="text" id="txt1" onFocus="SoftKeyboard(this)">