JavaScript 3단계 연계 영상 데이터 공유

 var oproc = document.getElementById("proc");
    var ocity = document.getElementById("city");
    var odist = document.getElementById("dist");
    
    window.onload = function(){
        for(var i =0;i<oProc.length;i++){
            //创建元素节点
            var oOpt = document.createElement("option");
            //创建文本节点
            var oTxt = document.createTextNode(oProc[i]);
            oOpt.appendChild(oTxt);
            oproc.appendChild(oOpt);
        }
    };
    function showCity(){
        if(oproc.value=="-1"){
            ocity.options.length = 1;
            odist.options.length = 1;
        }else{
            ocity.options.length = 1;
            odist.options.length = 1;
            var num = oproc.options.selectedIndex;
            //console.log(num); 测试是否成功
            for(var i =0;i<oCity[num-1].length;i++){ 
                var oOpt = document.createElement("option");
                var oTxt = document.createTextNode(oCity[num-1][i]);
                oOpt.appendChild(oTxt);
                ocity.appendChild(oOpt);
            }
        }
    }
    function showDist(){
        if(ocity.value==&#39;-1&#39;){
            odist.options.length = 1
        }else{
            odist.options.length = 1;
            var numPro = oproc.options.selectedIndex;
            var numCity = ocity.options.selectedIndex;
            for(var i=0;i<oDist[numPro-1][numCity-1].length;i++){
                var oOpt = document.createElement("option");
                var oTxt = document.createTextNode(oDist[numPro-1][numCity-1][i]);
                oOpt.appendChild(oTxt);
                odist.appendChild(oOpt);
            }
        }
    }