在IE 7,8,9或更低版本的浏览器中未显示链式下拉框值

Question

这是我的javascript代码:: ---

<script language="javascript" type="text/javascript">

//Browser Support Code
function ajaxFunction(str){
    var ajaxRequest;  // The variable that makes Ajax possible!

    try{
        // Opera 8.0+, Firefox, Safari
        ajaxRequest = new XMLHttpRequest();
    } catch (e){
        // Internet Explorer Browsers
        try{
            ajaxRequest = new ActiveXObject("Msxml2.XMLHTTP");
        } catch (e) {
            try{
                ajaxRequest = new ActiveXObject("Microsoft.XMLHTTP");
            } catch (e){
                // Something went wrong
                alert("Your browser broke!");
                return false;
            }
        }
    }
    // Create a function that will receive data sent from the server

    var url="../frontend/views/home/category.php" + "?value="+str;

    ajaxRequest.onreadystatechange = function(){
        if(ajaxRequest.readyState == 4){
            //document.myForm.time.value = ajaxRequest.responseText;
            document.getElementById("class").innerHTML=ajaxRequest.responseText;
        }
    }

    ajaxRequest.open("GET", url, true);
    ajaxRequest.send(null); 

}


</script>