For 循环返回未定义的变量

Question

var formobj = document.h1;
for (var j = 0; j < formobj.elements.length; j++) {
    if (formobj.elements[j].type == "radiobutton" && formobj.elements[j].checked) {
        var wholebase = formobj.elements[j].value;
    }
}

Later in the script, the variable is set to the inner html of a div and is labeled as undefined. Is there a flaw in my for loop?

Answer 1

There is no type radiobutton , I think you want type == 'radio' .

Answer 2

Your wholesale variable is defined within the inner scope. Once you leave this scope the variable no longer exists. Read about Javascript scope here or here . You can change your code like this:

var wholebase = null; //<-- declare the variable here
var formobj = document.h1;   
for (var j = 0; j < formobj.elements.length; j++){
        if (formobj.elements[j].type == "radiobutton" && formobj.elements[j].checked){
        wholebase = formobj.elements[j].value;
    }
}