用戶名<input class="yonghu" type="text" id="user" name="u" />

var $ = JQuery;

function test(){

var user = $("#user").val(); //獲取元素

var user =$(".yonghu").val();

alert(user);

}_

var user = $("input[type=password]").val();

function test(){

var user = document.getElementById("user");

alert(user.value);

user.value = user.value +"abc";

}

//jquery 遍歷數組

1.

var arr =[1,2,3,4,5,6,7,8,9,10],res=0;

$.each(arr,functin(i,v){//下標,值

res+=v

})

alert(res);

2.

$(arr).each(function(i,v){

res+=v

})

for(var i=0,i<arr.length;i++){

res+=arr[i];

}

alert(res);

js JQuery 獲取元素和遍歷