是否有一个JavaScript中的var_dump（PHP）等价物？
我们需要查看一个对象在Javascript中有什么方法/字段。
正如其他人所说，你可以使用Firebug，这将使你无需担心火狐。 Chrome和Safari都有一个内置的开发者控制台，它与Firebug的控制台有着几乎相同的界面，所以你的代码应该可以跨浏览器移植。 对于其他浏览器，还有Firebug Lite 。
如果Firebug不适合你，那么试试这个简单的脚本：
function dump(obj) { var out = ''; for (var i in obj) { out += i + ": " + obj[i] + "\n"; } alert(out); // or, if you wanted to avoid alerts... var pre = document.createElement('pre'); pre.innerHTML = out; document.body.appendChild(pre) }
我build议不要警惕每个单独的财产：一些物品有很多财产，你会在那里整天点击“确定”，“确定”，“确定”，“哦…该死的是我的财产寻找”。
如果你使用的是firefox，那么萤火虫插件控制台是一个很好的检查对象的方法
console.debug(myObject);
或者你可以循环遍历属性（包括方法），如下所示：
for (property in object) { // do what you want with property, object[property].value }
很多现代浏览器都支持以下语法：
JSON.stringify(myVar);
它不能说足够的，你可以使用console.debug（对象）。 如果你这样做的话，这种技术每年可以节省数百个小时：p
为了回答这个问题标题中的问题，下面是一个类似于PHP var_dump的函数。 它只在每次调用时转储一个variables，但是它指示数据types和值，它遍历数组和对象[即使它们是对象数组，反之亦然]。 我相信这可以改善。 我更像一个PHP的家伙。
/** * Does a PHP var_dump'ish behavior. It only dumps one variable per call. The * first parameter is the variable, and the second parameter is an optional * name. This can be the variable name [makes it easier to distinguish between * numerious calls to this function], but any string value can be passed. * * @param mixed var_value - the variable to be dumped * @param string var_name - ideally the name of the variable, which will be used * to label the dump. If this argumment is omitted, then the dump will * display without a label. * @param boolean - annonymous third parameter. * On TRUE publishes the result to the DOM document body. * On FALSE a string is returned. * Default is TRUE. * @returns string|inserts Dom Object in the BODY element. */ function my_dump (var_value, var_name) { // Check for a third argument and if one exists, capture it's value, else // default to TRUE. When the third argument is true, this function // publishes the result to the document body, else, it outputs a string. // The third argument is intend for use by recursive calls within this // function, but there is no reason why it couldn't be used in other ways. var is_publish_to_body = typeof arguments[2] === 'undefined' ? true:arguments[2]; // Check for a fourth argument and if one exists, add three to it and // use it to indent the out block by that many characters. This argument is // not intended to be used by any other than the recursive call. var indent_by = typeof arguments[3] === 'undefined' ? 0:arguments[3]+3; var do_boolean = function (v) { return 'Boolean(1) '+(v?'TRUE':'FALSE'); }; var do_number = function(v) { var num_digits = (''+v).length; return 'Number('+num_digits+') '+v; }; var do_string = function(v) { var num_chars = v.length; return 'String('+num_chars+') "'+v+'"'; }; var do_object = function(v) { if (v === null) { return "NULL(0)"; } var out = ''; var num_elem = 0; var indent = ''; if (v instanceof Array) { num_elem = v.length; for (var d=0; d<indent_by; ++d) { indent += ' '; } out = "Array("+num_elem+") \n"+(indent.length === 0?'':'|'+indent+'')+"("; for (var i=0; i<num_elem; ++i) { out += "\n"+(indent.length === 0?'':'|'+indent)+"| ["+i+"] = "+my_dump(v[i],'',false,indent_by); } out += "\n"+(indent.length === 0?'':'|'+indent+'')+")"; return out; } else if (v instanceof Object) { for (var d=0; d<indent_by; ++d) { indent += ' '; } out = "Object \n"+(indent.length === 0?'':'|'+indent+'')+"("; for (var p in v) { out += "\n"+(indent.length === 0?'':'|'+indent)+"| ["+p+"] = "+my_dump(v[p],'',false,indent_by); } out += "\n"+(indent.length === 0?'':'|'+indent+'')+")"; return out; } else { return 'Unknown Object Type!'; } }; // Makes it easier, later on, to switch behaviors based on existance or // absence of a var_name parameter. By converting 'undefined' to 'empty // string', the length greater than zero test can be applied in all cases. var_name = typeof var_name === 'undefined' ? '':var_name; var out = ''; var v_name = ''; switch (typeof var_value) { case "boolean": v_name = var_name.length > 0 ? var_name + ' = ':''; // Turns labeling on if var_name present, else no label out += v_name + do_boolean(var_value); break; case "number": v_name = var_name.length > 0 ? var_name + ' = ':''; out += v_name + do_number(var_value); break; case "string": v_name = var_name.length > 0 ? var_name + ' = ':''; out += v_name + do_string(var_value); break; case "object": v_name = var_name.length > 0 ? var_name + ' => ':''; out += v_name + do_object(var_value); break; case "function": v_name = var_name.length > 0 ? var_name + ' = ':''; out += v_name + "Function"; break; case "undefined": v_name = var_name.length > 0 ? var_name + ' = ':''; out += v_name + "Undefined"; break; default: out += v_name + ' is unknown type!'; } // Using indent_by to filter out recursive calls, so this only happens on the // primary call [ie at the end of the algorithm] if (is_publish_to_body && indent_by === 0) { var div_dump = document.getElementById('div_dump'); if (!div_dump) { div_dump = document.createElement('div'); div_dump.id = 'div_dump'; var style_dump = document.getElementsByTagName("style")[0]; if (!style_dump) { var head = document.getElementsByTagName("head")[0]; style_dump = document.createElement("style"); head.appendChild(style_dump); } // Thank you Tim Down [http://stackoverflow.com/users/96100/tim-down] // for the following addRule function var addRule; if (typeof document.styleSheets != "undefined" && document.styleSheets) { addRule = function(selector, rule) { var styleSheets = document.styleSheets, styleSheet; if (styleSheets && styleSheets.length) { styleSheet = styleSheets[styleSheets.length - 1]; if (styleSheet.addRule) { styleSheet.addRule(selector, rule) } else if (typeof styleSheet.cssText == "string") { styleSheet.cssText = selector + " {" + rule + "}"; } else if (styleSheet.insertRule && styleSheet.cssRules) { styleSheet.insertRule(selector + " {" + rule + "}", styleSheet.cssRules.length); } } }; } else { addRule = function(selector, rule, el, doc) { el.appendChild(doc.createTextNode(selector + " {" + rule + "}")); }; } // Ensure the dump text will be visible under all conditions [ie always // black text against a white background]. addRule('#div_dump', 'background-color:white', style_dump, document); addRule('#div_dump', 'color:black', style_dump, document); addRule('#div_dump', 'padding:15px', style_dump, document); style_dump = null; } var pre_dump = document.getElementById('pre_dump'); if (!pre_dump) { pre_dump = document.createElement('pre'); pre_dump.id = 'pre_dump'; pre_dump.innerHTML = out+"\n"; div_dump.appendChild(pre_dump); document.body.appendChild(div_dump); } else { pre_dump.innerHTML += out+"\n"; } } else { return out; } }
在firebug或google-chrome web-inspector中， console.dir （朝向链接页面的底部）将输出对象属性的交互式列表。
另请参阅Stack-O答案
如果使用Firebug，则可以使用console.log输出对象，并在控制台中获取超链接的可探测项目。
对于那些不知道variablestypes的人，nickf的function有点改进：
function dump(v) { switch (typeof v) { case "object": for (var i in v) { console.log(i+":"+v[i]); } break; default: //number, string, boolean, null, undefined console.log(typeof v+":"+v); break; } }
我改进了nickf的答案，所以recursion地遍历对象：
function var_dump(obj, element) { var logMsg = objToString(obj, 0); if (element) // set innerHTML to logMsg { var pre = document.createElement('pre'); pre.innerHTML = logMsg; element.innerHTML = ''; element.appendChild(pre); } else // write logMsg to the console { console.log(logMsg); } } function objToString(obj, level) { var out = ''; for (var i in obj) { for (loop = level; loop > 0; loop--) { out += " "; } if (obj[i] instanceof Object) { out += i + " (Object):\n"; out += objToString(obj[i], level + 1); } else { out += i + ": " + obj[i] + "\n"; } } return out; }
如果你正在寻找在JS中转换的PHP函数，有这个小网站： http ： //phpjs.org 。 在那里，你可以得到大部分的PHP函数可靠地写在JS中。 对于var_dump尝试： http : //phpjs.org/functions/var_dump/ （确保检查顶部的评论，这取决于“回声”，这也可以从同一个网站下载）
console.log(OBJECT|ARRAY|STRING|...); console.info(OBJECT|ARRAY|STRING|...); console.debug(OBJECT|ARRAY|STRING|...); console.warn(OBJECT|ARRAY|STRING|...); console.assert(Condition, 'Message if false');
这些应该可以正常工作在Google Chrome和Mozilla Firefox上（如果您使用的是旧版本的Firefox，那么您必须安装Firebug插件）
在Internet Explorer 8或更高版本中，您必须执行以下操作：
- 通过单击F12button启动“开发人员工具”
- 在选项卡列表中，点击“脚本”选项卡“
- 点击右侧的“控制台”button
有关更多信息，您可以访问以下URL： https ： //developer.chrome.com/devtools/docs/console-api
你想以JSON的forms看到整个对象（所有对象和variables的嵌套级别）。 JSON代表JavaScript对象表示法，并且打印出对象的JSONstring与var_dump （获取JavaScript对象的string表示forms）相当。 幸运的是，JSON在代码中非常易于使用，JSON数据格式也非常易读。
例：
var objectInStringFormat = JSON.stringify(someObject); alert(objectInStringFormat);
我用了第一个答案，但是我觉得错过了recursion。
结果是这样的：
function dump(obj) { var out = ''; for (var i in obj) { if(typeof obj[i] === 'object'){ dump(obj[i]); }else{ out += i + ": " + obj[i] + "\n"; } } var pre = document.createElement('pre'); pre.innerHTML = out; document.body.appendChild(pre); }
基于在这篇文章中发现的以前的function。 增加了recursion模式和缩进。
function dump(v, s) { s = s || 1; var t = ''; switch (typeof v) { case "object": t += "\n"; for (var i in v) { t += Array(s).join(" ")+i+": "; t += dump(v[i], s+3); } break; default: //number, string, boolean, null, undefined t += v+" ("+typeof v+")\n"; break; } return t; }
例
var a = { b: 1, c: { d:1, e:2, d:3, c: { d:1, e:2, d:3 } } }; var d = dump(a); console.log(d); document.getElementById("#dump").innerHTML = "<pre>" + d + "</pre>";
结果
b: 1 (number) c: d: 3 (number) e: 2 (number) c: d: 3 (number) e: 2 (number)
以下是我最喜欢的var_dump / print_r等效于Javascript到PHP var_dump 。
function dump(arr,level) { var dumped_text = ""; if(!level) level = 0; //The padding given at the beginning of the line. var level_padding = ""; for(var j=0;j<level+1;j++) level_padding += " "; if(typeof(arr) == 'object') { //Array/Hashes/Objects for(var item in arr) { var value = arr[item]; if(typeof(value) == 'object') { //If it is an array, dumped_text += level_padding + "'" + item + "' ...\n"; dumped_text += dump(value,level+1); } else { dumped_text += level_padding + "'" + item + "' => \"" + value + "\"\n"; } } } else { //Stings/Chars/Numbers etc. dumped_text = "===>"+arr+"<===("+typeof(arr)+")"; } return dumped_text; }
