常见用法
console.log( ) | info( ) | debug( ) | warn( ) | error( ) console.log("console log")console.info("console info")console.debug("console debug")console.warn("console warn")console.error("console error")这些控制台将依据提供给它们的事件类型，间接以适当的色彩打印原始字符串
测试Demo
<!DOCTYPE html><html lang="en"><head> <meta charset="UTF-8"> <title>Title</title></head><body> <script> console.log("console log") console.info("console info") console.debug("console debug") console.warn("console warn") console.error("console error") </script> <script> console.log("%cText color is green and increased font size", "color: green; font-size: 2rem;") </script> <script> console.log("Multiple styles: %cred %corange", "color: red", "color: orange", "Additional unformatted message"); </script> <script> let info1 = [["Suprabha"], ["Frontend Dev"], ["Javascript"]] console.table(info1) </script> <script> console.group() console.log("Test 1st message") console.group("info") console.log("Suprabha") console.log("Frontend Engineer") console.groupEnd() console.groupEnd() </script> <script> let info2 = { "name": "Suprabha", "designation": "Frontend Engineer", "social": "@suprabhasupi" } console.dir(info2) </script> <!-- console.dir --> <button>console.log打印触发对象</button> <button>console.dir打印触发对象</button> <script> console.log(document.body, 'bodyHtml'); console.dir(document.body); let oButton = document.getElementsByTagName('button'); oButton[0].onclick = function(event){ console.log(event.target, 'button1'); } oButton[1].onclick = function(event){ console.dir(event.target, 'button2'); } </script> <script> console.assert(false, "Log me!") </script> <script> let name = "supi" let msg = "Its not a number" console.assert(typeof msg === "number", {name: name, msg: msg}) </script> <script> console.count("Hey") console.count("Hey") console.count("Hey") console.count("Hey") </script> <script> for (let i = 0; i < 5; i++) { console.count() } </script> <script> console.time("Time") let l = 0; for (let i = 0; i < 5; i++) { l += i } console.log("total", l) console.timeEnd("Time") </script></body></html>款式控制台输入
能够应用% c 指令将 CSS 款式利用于控制台输入
console.log("%cText color is green and increased font size", "color: green; font-size: 2rem;")咱们能够屡次增加% c
console.log("Multiple styles: %cred %corange", "color: red", "color: orange", "Additional unformatted message");console.table( )
Table ()容许咱们在控制台中生成一个表。输出必须是一个数组或一个对象，该对象将以表的模式显示
let info = [["Suprabha"], ["Frontend Dev"], ["Javascript"]]console.table(info)group("group") & groupEnd("group")
要组织控制台，让咱们应用 console.group () & console.groupEnd ()
应用控制台组，将控制台日志分组在一起，而每个分组在层次结构中创立另一个级别。调用 groupEnd 缩小了一个
console.group() console.log("Test 1st message") console.group("info") console.log("Suprabha") console.log("Frontend Engineer") console.groupEnd()console.groupEnd()console.dir( )
打印指定对象的 JSON 示意模式
let info = { "name": "Suprabha", "designation": "Frontend Engineer", "social": "@suprabhasupi" }console.dir(info)间接打印json可能不显著，用来打印dom对象就显著比照
<button>console.log打印触发对象</button><button>console.dir打印触发对象</button><script> console.log(document.body, 'bodyHtml'); console.dir(document.body); let oButton = document.getElementsByTagName('button'); oButton[0].onclick = function(event){ console.log(event.target, 'button1'); } oButton[1].onclick = function(event){ console.dir(event.target, 'button2'); }</script>console.assert( )
如果第一个参数为 false，则记录音讯并将跟踪堆栈到控制台
它只会打印谬误的参数，如果第一个参数是真的，它什么也不会做
console.assert(false, "Log me!")let name = "supi"let msg = "Its not a number"console.assert(typeof msg === "number", {name: name, msg: msg})console.count ( )
这个函数记录调用 count ()的次数。这个函数承受一个可选的参数标签
如果提供了 label，此函数将记录应用该特定标签调用 count ()的次数
console.count("Hey")console.count("Hey")console.count("Hey")console.count("Hey")如果省略标签，函数将记录在这一行中调用 count ()的次数
for (let i = 0; i < 5; i++) { console.count()}time( ) and timeEnd( )
查看代码在执行时的性能,Time ()是一种更好的办法来跟踪 JavaScript 执行所破费的微工夫
console.time("Time")let l = 0;for (let i = 0; i < 5; i++) { l += i}console.log("total", l)console.timeEnd(