javascript 容易出问题的地方:
(1)把json 字符串转化为对象
var jsonStr='{"2":"1.2.3","3":"1.2.5"}'; var jsonObj2=eval("("+jsonStr+")");
注意:使用eval时,一定要在json字符串前后加上小括号
(2)
遍历js 对象属性
var jsonStr='{"2":"1.2.3","3":"1.2.5"}'; var jsonObj2=eval("("+jsonStr+")"); for(temp in jsonObj2){ alert(temp); }
说明:temp的取值为2和3. jsonStr的类型是string,jsonObj2的类型是object
(3)判断js变量是否有值
/** * whether has value * * @param {Object} * input */ isHasValue = function(input) { if (typeof input == "number" && input == "0") { return true; } if (input == "" || input == undefined || com.whuang.hsj.isWholeWhitespace(input)) { return false; } return true; }; isWholeWhitespace = function(inputString) { if (typeof inputString == "object") { return inputString; } var bootInit = true; if (inputString == "" || inputString == undefined) { return false; } for ( var i = 0; i < inputString.length; i++) { var c = inputString.charAt(i); if (!com.whuang.hsj.isWhitespace(c)) { bootInit = false; break; } } return bootInit; };
(4)把对象转化为json字符串
object2jsonStr=function(requestObj) { return JSON.stringify(requestObj); };
(5)把表单提交的query string转化为对象
/***
* convert [request query string] to [js object]
*/
var queryString2Object=function(queryString)
{
if(queryString==''||queryString==undefined)
{
return null;
}
var queryArray=queryString.split('&');
var queryObj=new Object();
for(var i=0;i<queryArray.length;i++)
{
var oneQuery=queryArray[i];
var oneQueryKeyValue=oneQuery.split('=');
if(oneQueryKeyValue.length>1)
{
queryObj[oneQueryKeyValue[0]]=oneQueryKeyValue[1];
}
}
return queryObj;
};
测试:
var queryString="name1=value1&name2=&name3=value3&name4=value4"; var a=com.whuang.hsj.queryString2Object(queryString); alert(a.name1);