201601241116_《Javascript优化（css,dom,loop）》

css:

oEl.style.cssText = "border-left:1px solid red";

dom:

1. document.createDocumentFragment();

2. var newDOM = oldDOM.cloneNode(true);

　　oldDOM.parentNode.replaceChild(newDOM,oldDom);

loop:

1. 

var i = 0;

for(;i< len;i++){

};

2.

var i = arr.length;

for(;i;i--){

　　console.log(arr[i]);

};