script Math

JavaScript Math Object
是一個擁有數學常數及數學函數。

<font size = 5><center> 常用 Math 數學的運算</center> <div border="2" class="Div" > <!--------------------------------------------------------------------> Math.round(x) : 將x四捨五入到整數。<br /> Math.round ( <input class="c" type="text" value="3.1416" /> ) = <nobr class="c"></nobr><br /> Math.round ( <input class="c" type="text" value="3.89" /> ) = <nobr class="c"></nobr></div> <!--------------------------------------------------------------------> <div border="2" class="Div"> Math.floor(x) : 將x往下減到整數。<br /> Math.floor ( <input class="c" type="text" value="4.2" /> ) = <nobr class="c"></nobr><br /> Math.floor ( <input class="c" type="text" value="4.8" /> ) = <nobr class="c"></nobr></div> <!-------------------------------------------------------------------> <div border="2" class="Div"> Math.pow(7,2) 返回7的2次方，即為7X7=49。<br /> Math.pow( <input class="c" type="text" value="7" />, <input class="c" type="text" value="2" /> ) = <nobr class="c"></nobr></div> <!-------------------------------------------------------------------> <div border="2" class="Div"> Math.sqrt(49) 表示49的平方根，即為\( \sqrt 49 \)=7。 <br />Math.sqrt( <input class="c" type="text" value="49" /> ) = <nobr class="c"></nobr></div> <!--------------------------------------------------------------------> <div border="2" class="Div"> Math.abs(x) : 將x轉成正數。( 將x轉成負數 張 x 成 -1 OK)<br /> Math.abs( <input class="c" type="text" value="-123" /> ) = <nobr class="c"></nobr></div> <!-------------------------------------------------------------------> <div border="2" class="Div"> Math.ceil(x) : 將x往上加到整數。<br /> Math.ceil( <input class="c" type="text" value="1.23" /> ) = <nobr class="c"></nobr></div> <!--------------------------------------------------------------------> <div border="2" class="Div"> Math.min() : 找出參數列表中最小的值。<br /> Math.min( <input class="c" type="text" value="88" />, <input class="c" type="text" value="33" />, <input class="c" type="text" value="22" />, <input class="c" type="text" value="44" /> ) = <nobr class="c"></nobr></div> <!------------------------------------------------------------------> <div border="2" class="Div"> Math.max() : 找出參數列表中最大的值。<br /> Math.max( <input class="c" type="text" value="88" />, <input class="c" type="text" value="33" />, <input class="c" type="text" value="22" />, <input class="c" type="text" value="44" /> ) = <nobr class="c"></nobr></div> <!--------------------------------------------------------------------------------------------------> <style> .Div input {width:80px} .Div {background-color: lavender; width: 90%;font-size: 20px ; border: 1px solid black; padding: 10px; } .Div:nth-child(2n+2) {background-color: orange} </style> <script>function OKf() { bb = document.getElementsByClassName("c"); bb[1].innerHTML = Math.round(bb[0].value); bb[3].innerHTML = Math.round(bb[2].value); bb[5].innerHTML = Math.floor(bb[4].value); bb[7].innerHTML = Math.floor(bb[6].value); bb[10].innerHTML = Math.pow(bb[8].value,bb[9].value); bb[12].innerHTML = Math.sqrt(bb[11].value); bb[14].innerHTML = Math.abs(bb[13].value); bb[16].innerHTML = Math.ceil(bb[15].value); bb[21].innerHTML = Math.min(bb[17].value,bb[18].value,bb[19].value, bb[20].value); bb[26].innerHTML = Math.max(bb[22].value,bb[23].value,bb[24].value,bb[25].value); } OKf(); </script> <script> function ISKey(event){ var charCode = (evt.which) ? evt.which : evt.keyCode; document.getElementById("kkk").innerHTML=charCode ; if (charCode == 13 ){ return true;}; if (charCode > 41 && charCode < 57){ return true;}; return false; } </script> <script> var Class= document.querySelectorAll(".c") ; Class.forEach((round) => { round.addEventListener("mouseover", function() { round.style.backgroundColor = "bisque"; round.focus() ; round.select() ; }) }) Class.forEach((round) => { round.addEventListener("mouseout", function() { round.style.backgroundColor = "ivory"; round.blur() ; }) }) Class.forEach((round) => { round.addEventListener("change", function() { round.select() ; OKf() ; }) }) </script>

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<style> #Random {font-size:20px;width:100%} #Random td{font-size:20px;padding:6px} </style> <font size = 5><center>Math.random() 偽隨機數</center> <table id="Random" border="1" > <tbody><tr> <th width="55%">函數</th><th width="20%">範圍</th><th width="25%">隨機數</th> <tr><td> Math.random()</td><td>random 0 to 1</td><td id="Ra1">第一行 欄位 2 <tr><td> Math.floor(Math.random()*10)</td><td>random 0 to 9</td><td id="Ra2"> <tr><td> Math.floor(Math.random()*10+1)</td><td> random 1 to 10</td><td id="Ra3"> <tr><td> Math.floor(Math.random()*100)</td><td> random 0 to 99</td><td id="Ra4"> <tr><td> Math.floor(Math.random()*100+1)</td><td> random 1 to 100</td><td id="Ra5"> <tr><td> var min=20, max=80<br> Math.floor(Math.random() * (max - min + 1) ) + min; </td><td> random 20 to 80</td><td id="Ra6"> </td></tr> </tbody> </table> <script> var qid ; function Ram(){ clearTimeout ( qid );Math.floor Ra1.innerHTML = Math.random().toFixed(15); Ra2.innerHTML = Math.floor(Math.random()*10); Ra3.innerHTML = Math.floor(Math.random()*10+1); Ra4.innerHTML = Math.floor(Math.random()*100); Ra5.innerHTML = Math.floor(Math.random()*100+1); var min=20, max=80 ; Ra6.innerHTML=Math.floor(Math.random() * (max - min + 1) ) + min; qid = setTimeout ( Ram, 1000 ); } Ram(); </script>

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<font size = 5><center>number.toFixed(x)<br> 小數點後有指定位數的數字</center><font size = 3> <pre> 1234.123456789.toFixed(0) = <script>document.write(1234.123456789.toFixed(0) ) </script> 1234.123456789.toFixed(2) = <script>document.write(1234.123456789.toFixed(2) ) </script> 1234.123456789.toFixed(5) = <script>document.write(1234.123456789.toFixed(5) ) </script> 1234.123456789.toFixed(30) = <script>document.write(1234.123456789.toFixed(30) ) </script> </pre>

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#html #網頁格式 #script #style #div #script 數字 小數點 toFixed() #script Math.round() #script Math.floor() #script Math.pow() #script Math.sqrt() #script Math.ceil() #script Math.random() 隨機數 #script Math 數字運算() #script Math.random()