我想看看JavaScript对象的结构(用于调试)。PHP中有类似var_dump的东西吗?
当前回答
将JSON响应解析为HTML的一个很好的简单解决方案。
var json_response = jQuery.parseJSON(data);
html_response += 'JSON Response:<br />';
jQuery.each(json_response, function(k, v) {
html_response += outputJSONReponse(k, v);
});
function outputJSONReponse(k, v) {
var html_response = k + ': ';
if(jQuery.isArray(v) || jQuery.isPlainObject(v)) {
jQuery.each(v, function(j, w) {
html_response += outputJSONReponse(j, w);
});
} else {
html_response += v + '<br />';
}
return html_response;
}
其他回答
大多数现代浏览器在开发人员工具中都有一个控制台,这对这种调试很有用。
console.log(myvar);
然后你将在控制台中得到对象/任何东西的良好映射接口。
查看控制台文档了解更多详细信息。
Firebug。
然后,在javascript中:
var blah = {something: 'hi', another: 'noway'};
console.debug("Here is blah: %o", blah);
现在你可以查看控制台,点击语句,看看里面有什么
我写了这个JS函数dump()来像PHP的var_dump()一样工作。 要在警报窗口中显示变量的内容:dump(variable) 要在网页中显示变量的内容:dump(variable, 'body') 获取变量的字符串:dump(variable, 'none')
/* repeatString() returns a string which has been repeated a set number of times */
function repeatString(str, num) {
out = '';
for (var i = 0; i < num; i++) {
out += str;
}
return out;
}
/*
dump() displays the contents of a variable like var_dump() does in PHP. dump() is
better than typeof, because it can distinguish between array, null and object.
Parameters:
v: The variable
howDisplay: "none", "body", "alert" (default)
recursionLevel: Number of times the function has recursed when entering nested
objects or arrays. Each level of recursion adds extra space to the
output to indicate level. Set to 0 by default.
Return Value:
A string of the variable's contents
Limitations:
Can't pass an undefined variable to dump().
dump() can't distinguish between int and float.
dump() can't tell the original variable type of a member variable of an object.
These limitations can't be fixed because these are *features* of JS. However, dump()
*/
function dump(v, howDisplay, recursionLevel) {
howDisplay = (typeof howDisplay === 'undefined') ? "alert" : howDisplay;
recursionLevel = (typeof recursionLevel !== 'number') ? 0 : recursionLevel;
var vType = typeof v;
var out = vType;
switch (vType) {
case "number":
/* there is absolutely no way in JS to distinguish 2 from 2.0
so 'number' is the best that you can do. The following doesn't work:
var er = /^[0-9]+$/;
if (!isNaN(v) && v % 1 === 0 && er.test(3.0)) {
out = 'int';
}
*/
break;
case "boolean":
out += ": " + v;
break;
case "string":
out += "(" + v.length + '): "' + v + '"';
break;
case "object":
//check if null
if (v === null) {
out = "null";
}
//If using jQuery: if ($.isArray(v))
//If using IE: if (isArray(v))
//this should work for all browsers according to the ECMAScript standard:
else if (Object.prototype.toString.call(v) === '[object Array]') {
out = 'array(' + v.length + '): {\n';
for (var i = 0; i < v.length; i++) {
out += repeatString(' ', recursionLevel) + " [" + i + "]: " +
dump(v[i], "none", recursionLevel + 1) + "\n";
}
out += repeatString(' ', recursionLevel) + "}";
}
else {
//if object
let sContents = "{\n";
let cnt = 0;
for (var member in v) {
//No way to know the original data type of member, since JS
//always converts it to a string and no other way to parse objects.
sContents += repeatString(' ', recursionLevel) + " " + member +
": " + dump(v[member], "none", recursionLevel + 1) + "\n";
cnt++;
}
sContents += repeatString(' ', recursionLevel) + "}";
out += "(" + cnt + "): " + sContents;
}
break;
default:
out = v;
break;
}
if (howDisplay == 'body') {
var pre = document.createElement('pre');
pre.innerHTML = out;
document.body.appendChild(pre);
}
else if (howDisplay == 'alert') {
alert(out);
}
return out;
}
在JavaScript中等效的var_dump ?很简单,没有。
但这并不意味着你就无能为力了。就像一些人建议的那样,使用Firebug(或其他浏览器中的等效工具),但与其他人建议的不同的是,当你有(稍微)更好的工具console.dir时,不要使用console.log:
console.dir(object)
打印对象的所有属性的交互式列表。这 看起来与您在DOM选项卡中看到的视图相同。
将JSON响应解析为HTML的一个很好的简单解决方案。
var json_response = jQuery.parseJSON(data);
html_response += 'JSON Response:<br />';
jQuery.each(json_response, function(k, v) {
html_response += outputJSONReponse(k, v);
});
function outputJSONReponse(k, v) {
var html_response = k + ': ';
if(jQuery.isArray(v) || jQuery.isPlainObject(v)) {
jQuery.each(v, function(j, w) {
html_response += outputJSONReponse(j, w);
});
} else {
html_response += v + '<br />';
}
return html_response;
}
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