Print / display a JavaScript variable's name i

问题:

Is it possible to print / display a JavaScript variable's name? For example:

var foo=5;
var bar=6;
var foobar=foo+bar;

document.write(foo+ "<br>");
document.write(bar+ "<br>");
document.write(foobar + "<br>");

How would we print the variable's names so the output would be:

foo 
bar 
foobar

Rather than:

5
6
11

回答1:

You can put the variables in an object then easily print them this way: http://jsfiddle.net/5MVde/7/

See fiddle for everything, this is the JavaScript...

var x = {
    foo: 5,
    bar: 6,
    foobar: function (){
        var that=this;
        return that.foo+that.bar
    }
};

var myDiv = document.getElementById("results");

myDiv.innerHTML='Variable Names...';
for(var variable in x)
{
    //alert(variable);
    myDiv.innerHTML+='<br>'+variable;
}

myDiv.innerHTML+='<br><br>And their values...';
myDiv.innerHTML+='<br>'+x.foo+'<br>'+x.bar+'<br>'+x.foobar();

The JavaScript for...in statement loops through the properties of an object.

Another variation (thanks @elclanrs) if you don't want foobar to be a function: http://jsfiddle.net/fQ5hE/2/

回答2:

Utils = {
    eventRegister_globalVariable : function(variableName,handlers){
        eventRegister_JsonVariable(this,variableName,handlers);
    },
    eventRegister_jsonVariable : function(jsonObj,variableName,handlers){
        if(jsonObj.eventRegisteredVariable === undefined) {
            jsonObj.eventRegisteredVariable={};//this Object is used for trigger event in javascript variable value changes ku
        }
        Object.defineProperty(jsonObj, variableName , {
                    get: function() { 
                        return jsonObj.eventRegisteredVariable[variableName] },
                    set: function(value) {
                        jsonObj.eventRegisteredVariable[variableName] = value; handlers(jsonObj.eventRegisteredVariable[variableName]);}
                    });
            }

回答3:

Another possible solution can be "Object.keys(this)".... This will give you all the variable names in an array.