JS uses for loop to traverse child nodes to find elements_javascript tips

This article mainly introduces JS using for loop and array to traverse child nodes to find elements

function nextChildNode(node,clazz,tagName){
var count= node.childElementCount;
for(var i=0;i<count;i++){
if(node==undefined || node.children[i]==undefined){
continue;
}
if(clazz){
if(node.children[i].getAttribute('class')==clazz){
return node.children[i];
}
}else{
if(node.children[i].tagName==tagName){
return node.children[i];
}
}


}
return null;
}

function getChildNode(node,classArg,tagNodeArg){
for(var i=0;i<classArg.length;i++){
node=nextChildNode(node,classArg[i]);
}
for(var i=0;i<tagNodeArg.length;i++){
node=nextChildNode(node,null,tagNodeArg[i]);
}
return node;
}

function getItemId(node){
var classNode=['itemInfo','itemDesc'],tagNode=['P','BUTTON'];
node=getChildNode(node,classNode,tagNode);
alert(node.getAttribute('itemid'));

}

#调用函数
getItemId($(".shopItem")[0]);