jQuery - AJAX to change the value in an Input box

I made a form with two input boxes, one with an id of vaue2 and another with an id of value3. The value in the value3 input gets loaded with a value from the database when I tab from value2 to value3. This is the form:

<form action="{{.Page}}" name="form1" id="form1" method="POST" target="iframename" onsubmit="event.stopPropagation(); event.preventDefault();">
<table id="input4Form" style="vertical-align: middle;">
	<tr>
		<td></td><td colspan="4"><b>{{.Title}}</b></td>
	</tr>
	<tr>
		<td style="text-align: right;">{{.Label1}}</td>
		<td><input id="value1" type="text" name="value1" title="{{.In1_Title}}" maxlength="60" onkeydown="if (event.keyCode == 13) document.getElementById('input2search').click()"/></td>
		<td>  </td>
		<td style="text-align: right">{{.Label2}}</td>
		<td><input id="value2" type="text" name="value2" title="{{.In2_Title}}" maxlength="60" onkeydown="if (event.keyCode == 13) document.getElementById('input2search').click()"/></td>
		<td>  </td>
		<td style="text-align: right">{{.Label3}}</td>
		<td><input id="value3" type="text" name="value3" title="{{.In3_Title}}" maxlength="60" onkeydown="if (event.keyCode == 13) document.getElementById('input2search').click()"/></td>
		<td>  </td>
		<td><input type="button" id="input2search" value="   Go   " onclick="event.stopPropagation(); event.preventDefault();loadBySubmit2('form1');"/>
		</td>
	</tr>
</table>
</form>
<script type="text/javascript">
	document.getElementById('value2').addEventListener('keydown', getdefAD);
	document.getElementById('value1').focus();

	function getdefAD(val1){	
		if (val1.keyCode == 9) {
			$.post('erp/getDefaultValue?attr=' + $("input#value2").val() +'&id=' + $("input#value1").val(), function(data) {
			if (data) $("input#value3").val(data);
   		});	
		}
	}
</script>

This is the response handler to return a value from the database:

//Get default value for attribute
func getDefaultValue(w http.ResponseWriter, r *http.Request) {
	sA := "attr"
	sP := r.URL.Query().Get(sA)
	sA = "id"
	sI := r.URL.Query().Get(sA)
	if dataAccess.IsStringInSlice(sP, dataAccess.SlcAD_Default) {
		sR := dataAccess.GetERPADDefault(sP, sI)
		fmt.Fprintf(w, "%s", sR)
	} else {
		//sR = dataAccess.GetERPADDefault(sP, sI)
		//fmt.Fprintf(w, "%s", sR)
		// fmt.Println("Not found")
		return
	}
}