js基于json的级联下拉框

html>
script type="text/javascript">
/**  基于json的级联下拉列表，支持初始化
   调用eg：
       var comboselect = ComboSelectFactory(data, ‘p1‘, ‘p2‘, ‘p3‘, ‘p4‘);
       
   设定下拉列表value,text,parentid名称的方法eg:
    comboselect.setProperties({id:‘id‘,text:‘text‘,parentid:‘parentid‘,defaultvalue:‘defaultvalue‘});
    
   初始化下拉列表集合的方法eg:
    comboselect.initSelect(‘gd‘);
 */
 
 

var ComboSelectFactory = function(data){
    var comboselect = new ComboSelect(arguments);
    return comboselect;
}

var ComboSelect = function(data){
    this.myData = [].slice.call(data, 0, 1)[0];
    this.ids = [].slice.call(data, 1);
    this.setProperties({});

}

ComboSelect.prototype.setProperties = function(opt){
    this.defaultvalue = opt.defaultvalue || ‘-‘;
    this.id = opt.id || ‘id‘;
    this.text = opt.text || ‘categoryname‘;
    this.parent = opt.parent || ‘parentid‘;

    for(var i=0, len=this.ids.length-1; ilen; i++){
        var o = this.$(this.ids[i]);
        this.addEventHandler(o, ‘change‘, this.eventHandle(o,i));
    }

    this.initChild(null, 0);
}

ComboSelect.prototype.eventHandle = function(o,i) {
    var self = this;
    var oreg=o;
    var index=i+1;
    return function() {
        self.initChild(oreg, index);
    }
}

ComboSelect.prototype.initChild = function(oSelect, index){
    var p = null == oSelect ? this.defaultvalue : oSelect.options[oSelect.selectedIndex].value;
    var ds = this.getChilds(p);
    this.clearSelect(index);
    var child = this.$(this.ids[index]);
    for(var i=0, len=ds.length; ilen; i++){
        var currentObj = ds[i];
        child.options[child.length] = new Option(currentObj[this.text], currentObj[this.id]);
    }
}

ComboSelect.prototype.clearSelect = function(index) {
    for(var i=index, len=this.ids.length; ilen; i++){
        this.$(this.ids[i]).length=1;
    }
}

ComboSelect.prototype.getChilds = function(p) {
    var childs = [];
    for(var i=0, len=this.myData.length; ilen; i++){
        if(p == this.myData[i][this.parent]){
            childs.push(this.myData[i]);
        }
    }
    return childs;
}

ComboSelect.prototype.initSelect = function(id){
    var parentids = [];
    parentids = this.getParent(id);
    for (var i=0, len=this.ids.length; ilen; i++){    
        if(i==0){
            this.initChild(null, 0);
        }else{
            this.initChild(this.$(this.ids[i-1]),i);
        }
        this.$(this.ids[i]).value = parentids[i][this.id];
    }
}

ComboSelect.prototype.getParent = function(id) {
    var parents = [];
    for(var i=0, len=this.myData.length; ilen; i++){
        if(id == this.myData[i][this.id]){
            if(this.myData[i][this.parent] == this.defaultvalue){            
                parents.push(this.myData[i]);
                break;
            }else{
                parents = this.getParent(this.myData[i][this.parent]);            
                parents.push(this.myData[i]);
            }
        }
    }
    return parents;
}

ComboSelect.prototype.$ = function(sid) {
    return document.getElementById(sid);
}

ComboSelect.prototype.addEventHandler = function(oTarget, sEventType, fnHandler) {
    if (oTarget.addEventListener) {
        oTarget.addEventListener(sEventType, fnHandler, false);
    } else if (oTarget.attachEvent) {
        oTarget.attachEvent("on" + sEventType, fnHandler);
    } else {
        oTarget["on" + sEventType] = fnHandler;
    }
}

/*-- 扩展的级联 ---------------------------*/
    var data = [];

    data.push({id:‘cn‘, text:‘中国‘, parentid:‘-‘});

    data.push({id:‘fj‘, text:‘福建‘, parentid:‘cn‘});
    data.push({id:‘gd‘, text:‘广东‘, parentid:‘cn‘});

    data.push({id:‘fz‘, text:‘福州‘, parentid:‘fj‘});
    data.push({id:‘xm‘, text:‘厦门‘, parentid:‘fj‘});
    data.push({id:‘ly‘, text:‘龙岩‘, parentid:‘fj‘});

    data.push({id:‘fz-fq‘, text:‘福州1‘, parentid:‘fz‘});
    data.push({id:‘fz-mh‘, text:‘福州2‘, parentid:‘fz‘});
    data.push({id:‘fz-cl‘, text:‘福州3‘, parentid:‘fz‘});

    data.push({id:‘xm-dn‘, text:‘厦门1‘, parentid:‘xm‘});
    data.push({id:‘xm-jm‘, text:‘厦门2‘, parentid:‘xm‘});
    data.push({id:‘xm-xl‘, text:‘厦门3‘, parentid:‘xm‘});

    data.push({id:‘yl-xl‘, text:‘龙岩1‘, parentid:‘ly‘});
    data.push({id:‘yl-lc‘, text:‘龙岩2‘, parentid:‘ly‘});
    data.push({id:‘yl-sh‘, text:‘龙岩3‘, parentid:‘ly‘});
    data.push({id:‘yl-wp‘, text:‘龙岩4‘, parentid:‘ly‘});

    data.push({id:‘gz‘, text:‘广州‘, parentid:‘gd‘});
    data.push({id:‘sz‘, text:‘深圳‘, parentid:‘gd‘});
    data.push({id:‘mx‘, text:‘梅县‘, parentid:‘gd‘});

    data.push({id:‘gz-fq‘, text:‘广州1‘, parentid:‘gz‘});
    data.push({id:‘gz-mh‘, text:‘广州2‘, parentid:‘gz‘});
    data.push({id:‘gz-cl‘, text:‘广州3‘, parentid:‘gz‘});

    data.push({id:‘sz-dn‘, text:‘深圳1‘, parentid:‘sz‘});
    data.push({id:‘sz-jm‘, text:‘深圳2‘, parentid:‘sz‘});
    data.push({id:‘sz-xl‘, text:‘深圳3‘, parentid:‘sz‘});

    data.push({id:‘mx-xl‘, text:‘梅县1‘, parentid:‘mx‘});
    data.push({id:‘mx-lc‘, text:‘梅县2‘, parentid:‘mx‘});
    data.push({id:‘mx-sh‘, text:‘梅县3‘, parentid:‘mx‘});
    data.push({id:‘mx-wp‘, text:‘梅县4‘, parentid:‘mx‘});

    data.push({id:‘am‘, text:‘美国‘, parentid:‘-‘});

    data.push({id:‘ny‘, text:‘纽约‘, parentid:‘am‘});
    data.push({id:‘hsd‘, text:‘华盛顿‘, parentid:‘am‘});

function makeArray(arg1, arg2){
    return [ this, arg1, arg2 ];
}
//在onload后执行
window.onload = function() {
    comboselect = ComboSelectFactory(data, ‘p1‘, ‘p2‘, ‘p3‘, ‘p4‘);
    comboselect.setProperties({id:‘id‘,text:‘text‘});
}
script>
body>   
    select id="p1">option>-选择-option>select>br/>   
    select id="p2">option>-选择-option>select>br/>   
    select id="p3">option>-选择-option>select>br/>   
    select id="p4">option>-选择-option>select>   
body>  

html>