<script language="javascript">
function setValue(){
var w=0,arrChk=document.getElementsByName('chk'),arrTxt=document.getElementsByName('txt');
for(var i=0;i<3;i++){
if(arrChk[i].checked)w++;
arrTxt[i].value='';
}
if(w==0)return;
for(var i=0;i<3;i++){
if(arrChk[i].checked)arrTxt[i].value=(i==2&&w==3?34:parseInt(100/w))
}
}
</script><div align="center">
<input type="checkbox" name="chk" onclick="setValue()"><input type="text" name="txt">
<input type="checkbox" name="chk" onclick="setValue()"><input type="text" name="txt">
<input type="checkbox" name="chk" onclick="setValue()"><input type="text" name="txt">
</div>
function setValue(){
var w=0,arrChk=document.getElementsByName('chk'),arrTxt=document.getElementsByName('txt');
for(var i=0;i<3;i++){
if(arrChk[i].checked)w++;
arrTxt[i].value='';
}
if(w==0)return;
for(var i=0;i<3;i++){
if(arrChk[i].checked)arrTxt[i].value=(i==2&&w==3?34:parseInt(100/w))
}
}
</script><div align="center">
<input type="checkbox" name="chk" onclick="setValue()"><input type="text" name="txt">
<input type="checkbox" name="chk" onclick="setValue()"><input type="text" name="txt">
<input type="checkbox" name="chk" onclick="setValue()"><input type="text" name="txt">
</div>
function checkedit(form,len){
var isnull;
isnull = false;
var qua = 0;
for(i=0;i<form.elements.length;i++){
if(form.elements[i].type=="checkbox"&&form.elements[i].name=="checkit"){
if(form.elements[i].checked==true){
qua++;
isnull = true;
}
}
}
for(i=0;i<form.elements.length;i++){
if(form.elements[i].type=="checkbox"&&form.elements[i].name=="checkit"){
if(form.elements[i].checked==true){
form.elements[i+1].value = 100/qua;
isnull = true;
}
}
}
if(isnull == false){
alert("no select ");
}
}
</script>
<form name= "test123"><br>
<input type= "checkbox" name= "checkit"><input type= "text" name= "textit" value= ""><br>
<input type= "checkbox" name= "checkit"><input type= "text" name= "textit" value= ""><br>
<input type= "checkbox" name= "checkit"><input type= "text" name= "textit" value= ""><br>
<input type= "button" name= "button" value= "button" onclick= "javascript:checkedit(this.form,1)"><br>
</form>