如何替换名称属性

Question

I have this PHP output:

$total.":".$newId;

When success the function live_update() echo response back. I need to split PHP output into $total & $newId and change the existing input name attribute to the $newId. To do this, I tried my best for hours but I didn't succeed. Any help will be highly appreciated. This is the live_update() function:

<script>
    function live_update(el) {
        var str = el.value ;
        var id  = el.id ;
        var name= el.name;
        
        if (str.length==0) { 
        document.getElementById("live_update").innerHTML="";
        
        return;
      }

      if (window.XMLHttpRequest) 
      {
        xmlhttp=new XMLHttpRequest();
      }
        
      xmlhttp.onreadystatechange=function() {
            var Resp = this.responseText;
            var SplitedId = id.split(".");  
          
            if(SplitedId[1] == "di")
            {
                var Fres = Resp.split(":");
                document.getElementsByName(name).name=Fres[1];
                var Total = Fres[0];
            }else{
                var Total = Resp;
            }
          
        
    if (this.readyState==4 && this.status==200) {
        document.getElementById("live_update").innerHTML=Total;
        document.getElementsByName("coupon_row").style.disabled='none';
        
     }
    }
      
      xmlhttp.open("GET","profiles.php?act=live_update&u_key={u_key}&name="+name+"&id="+id+"&q="+str,true);
      xmlhttp.send();
    }
</script>

Answer 1

Change

document.getElementsByName(name).name=Fres[1];

to

document.getElementsByName(name)[0].setAttribute('name', Fres[1]);

guessing that you want a way to change name of a single element. you can do as above.

if there are multiple elements with same name, simply iterate and change name with

el.setAttribute('name', Fres[1])

Hope it works!

Answer 2

You should use the setAttribute() method to set a name to a HTML element. So, this is how it goes,

document.getElementsByName(name)[0].setAttribute("name", Fres[1]);

And document.getElementsByName() returns a list of elements so since you need the first element gotta use [0] index and set the name as shown.
If you want to update the same element you passed in live_update(el) you can simply do this

el.setAttribute("name", Fres[1]);