从jscript中的值查找属性名称

Question

如果我知道定义为的对象的值，则尝试获取属性名称

expOperators = {
    "0": "Select operator",
    "GREATERTHAN": "After",
    "LESSTHAN": "Before",
    "GREATERTHANEQUALTO": "On or After",
    "LESSTHANEQUALTO": "On or Before",
    "EQUALS": "On",
    "BETWEEN": "Between",
    "ISNULL": "Is Null",
    "ISNOTNULL": "Is not Null"
};

显然，如果我需要找到价值，这将很容易，但是我需要完成相反的任务，知道价值才能找出其实质。 任何想法？

Answer 1

您也将遍历对象，并将对象值与所需内容进行比较。

expOperators = {
    "0": "Select operator",
    "GREATERTHAN": "After",
    "LESSTHAN": "Before",
    "GREATERTHANEQUALTO": "On or After",
    "LESSTHANEQUALTO": "On or Before",
    "EQUALS": "On",
    "BETWEEN": "Between",
    "ISNULL": "Is Null",
    "ISNOTNULL": "Is not Null"
};

for(var name in expOperators ) {
    if(expOperators[name] === "Between"){
        document.write(name);
    }
}

http://jsfiddle.net/WsjyS/2/

Answer 2

用这样的东西

 for(var name in expOperators ) {
    if(expOperators.hasOwnProperty(name)){
      if(expOperators[name] === "Between"){
         alert(name);
       }
    }
}