Math物件可以執行方法做數學的運算。

JavaScript的Math物件可以執行方法做數學的運算。

<font size = 6><center>Math物件可以執行方法做數學的運算</center><div border="2" class="Div" >Math.round(x) : 將x四捨五入到整數。<br />Math.round ( <input class="c" onchange="OKf();this.select()" onkeypress="return ISKey(event)" onmouseover="this.select()" type="text" value="3.1416" /> ) = <nobr class="c"></nobr><br />Math.round ( <input class="c" onchange="OKf();this.select()" onkeypress="return ISKey(event)" onmouseover="this.select()" 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" onchange="OKf();this.select()" onkeypress="return ISKey(event)" onmouseover="this.select()" type="text" value="4.2" /> ) = <nobr class="c"></nobr><br />Math.floor ( <input class="c" onchange="OKf();this.select()" onkeypress="return ISKey(event)" onmouseover="this.select()" 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" onchange="OKf();this.select()" onkeypress="return ISKey(event)" onmouseover="this.select()" type="text" value="7" />, <input class="c" onchange="OKf();this.select()" onkeypress="return ISKey(event)" onmouseover="this.select()" 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" onchange="OKf();this.select()" onkeypress="return ISKey(event)" onmouseover="this.select()" 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" onchange="OKf();this.select()" onkeypress="return ISKey(event)" onmouseover="this.select()" 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" onchange="OKf();this.select()" onkeypress="return ISKey(event)" onmouseover="this.select()" 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" onchange="OKf();this.select()" onkeypress="return ISKey(event)" onmouseover="this.select()" type="text" value="88" />, <input class="c" onchange="OKf();this.select()" onkeypress="return ISKey(event)" onmouseover="this.select()" type="text" value="33" />, <input class="c" onchange="OKf();this.select()" onkeypress="return ISKey(event)" onmouseover="this.select()" type="text" value="22" />, <input class="c" onchange="OKf();this.select()" onkeypress="return ISKey(event)" onmouseover="this.select()" 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" onchange="OKf();this.select()" onkeypress="return ISKey(event)" onmouseover="this.select()" type="text" value="88" />, <input class="c" onchange="OKf();this.select()" onkeypress="return ISKey(event)" onmouseover="this.select()" type="text" value="33" />, <input class="c" onchange="OKf();this.select()" onkeypress="return ISKey(event)" onmouseover="this.select()" type="text" value="22" />, <input class="c" onchange="OKf();this.select()" onkeypress="return ISKey(event)" onmouseover="this.select()" 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>

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<a href="https://html.ug5g.com/search/label/script%20%E6%96%87%E5%AD%97%E6%95%B8%E5%AD%97%20Math%28%29" target="_blank" style=" text-decoration: none;" ><font size = 6><center>#文字 轉換 數字</center></a> <table style="width:100%;float:left;font-size: 20px ;"><tbody><tr><td><a href="https://html.ug5g.com/search/label/script%20%E6%96%87%E5%AD%97%E6%95%B8%E5%AD%97%20Math%28%29" target="_blank" style=" text-decoration: none;" >#string to number</a></td><td><a href="https://html.ug5g.com/search/label/script%20%E6%96%87%E5%AD%97%E6%95%B8%E5%AD%97%20Math%28%29" target="_blank" style=" text-decoration: none;">#parseInt()</a></td><td><a href="https://html.ug5g.com/search/label/script%20%E6%96%87%E5%AD%97%E6%95%B8%E5%AD%97%20Math%28%29" target="_blank" style=" text-decoration: none;">#parseFloat()</a></td></tr></tbody><table><br><br> <div id="DP"></div><script>var txt=""; txt += '<table border="5" style="width:45%;float:left;font-size: 20px ;"><tbody>' ; txt += ' <tr><td>parseInt(string)' ; txt += ' <tr><td>parseInt("5") </td><td>'; txt += parseInt("5") + '</td></tr>' ; txt += ' <tr><td>parseInt("10.123") </td><td>'; txt += parseInt("10.123") + '</td></tr>' ; txt += ' <tr><td>parseInt("10.33") </td><td>'; txt += parseInt("10.33") + '</td></tr>' ; txt += ' <tr><td>parseInt("34 45 66") </td><td>'; txt += parseInt("34 45 66") + '</td></tr>' ; txt += ' <tr><td>parseInt(" 60 ") </td><td>'; txt += parseInt(" 60 ") + '</td></tr>' ; txt += ' <tr><td>parseInt("40 years") </td><td>'; txt += parseInt("40 years") + '</td></tr>' ; txt += ' <tr><td>parseInt("He was 40") </td><td>'; txt += parseInt("He was 40") + '</td></tr>' ; txt += ' <tr><td>parseInt("10", 5) </td><td>'; txt += parseInt("10", 5) + '</td></tr>' ; txt += ' <tr><td>parseInt("010") </td><td>'; txt += parseInt("010") + '</td></tr>' ; txt += ' <tr><td>parseInt("10", 8) </td><td>'; txt += parseInt("10", 8) + '</td></tr>' ; txt += ' <tr><td> parseInt("0x10") </td><td>'; txt += parseInt("0x10") + '</td></tr>' ; txt += ' <tr><td> parseInt("10", 16) </td><td>'; txt += parseInt("10", 16) + '</td></tr>' ; txt += '</td></tr></tbody></table>' ; txt += '<table border="5" style="width:45%;font-size: 20px ;"><tbody>' ; txt += ' <tr><td>parseFloat(string)' ; txt += ' <tr><td>parseFloat("5") </td><td>'; txt += parseFloat("5") + '</td></tr>' ; txt += ' <tr><td>parseFloat("10.123") </td><td>'; txt += parseFloat("10.123") + '</td></tr>' ; txt += ' <tr><td>parseFloat("10.33") </td><td>'; txt += parseFloat("10.33") + '</td></tr>' ; txt += ' <tr><td>parseFloat("34 45 66") </td><td>'; txt += parseFloat("34 45 66") + '</td></tr>' ; txt += ' <tr><td>parseFloat(" 60 ") </td><td>'; txt += parseFloat(" 60 ") + '</td></tr>' ; txt += ' <tr><td>parseFloat("40 years") </td><td>'; txt += parseFloat("40 years") + '</td></tr>' ; txt += ' <tr><td>parseFloat("He was 40") </td><td>'; txt += parseFloat("He was 40") + '</td></tr>' ; txt += ' <tr><td>parseFloat("10", 5) </td><td>'; txt += parseFloat("10", 5) + '</td></tr>' ; txt += ' <tr><td>parseFloat("010") </td><td>'; txt += parseFloat("010") + '</td></tr>' ; txt += ' <tr><td>parseFloat("10", 8) </td><td>'; txt += parseFloat("10", 8) + '</td></tr>' ; txt += ' <tr><td> parseFloat("0x10") </td><td>'; txt += parseFloat("0x10") + '</td></tr>' ; txt += ' <tr><td> parseFloat("10", 16) </td><td>'; txt += parseFloat("10", 16) + '</td></tr>' ; txt += '</td></tr></tbody></table>' ; DP.innerHTML = txt; </script>

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<font size =6><pre> 從字符串中抽取 指定數目的字符。<br /></pre><table style="width:100%;font-size:30px;" ><tbody><tr><td><a href="https://html.ug5g.com/search/label/script%20%E6%96%87%E5%AD%97%E6%95%B8%E5%AD%97%20Math%28%29" target="_blank" style="text-decoration:none" >#substr()</a></td><td><a href="https://html.ug5g.com/search/label/script%20%E6%96%87%E5%AD%97%E6%95%B8%E5%AD%97%20Math%28%29" target="_blank" style="text-decoration:none" > #substring() </a></td><td><a href="https://html.ug5g.com/search/label/script%20%E6%96%87%E5%AD%97%E6%95%B8%E5%AD%97%20Math%28%29" target="_blank" style="text-decoration:none" > #indexOf() </a></td><td><a href="https://html.ug5g.com/search/label/script%20%E6%96%87%E5%AD%97%E6%95%B8%E5%AD%97%20Math%28%29" target="_blank" style="text-decoration:none" > #slice() </a></td><td><a href="https://html.ug5g.com/search/label/script%20%E6%96%87%E5%AD%97%E6%95%B8%E5%AD%97%20Math%28%29" target="_blank" style="text-decoration:none" > #length </a></td></tr></tbody></table><!---------------------------------------------------------------------> <style>#d1786516 {font-size:16px;} #d1786516 input {width:30px} input:hover{} </style><!----------------------------------------------><br /><table id="d1786516" border="1" cellpadding ="3" bgcolor="cornsilk"><tbody><tr><td width="300px" >var TxT = "0123456789ABCDEF" </td><td>設定 變數 TxT 為 0123456789ABCDEF。 </td></tr><!-----------------------------------------------------------><td><script>var TxT = "0123456789ABCDEF"; document.write('TxT.length = '+ TxT.length ) </script></td><td>判斷元素 變數 TxT 內有幾多個字。</td></tr><!----------------------------------------------------------><td>TxT.substr ( <input onchange="stef();this.select()" onmouseover="this.select()" onkeypress="return ISKey1(event)" class="cstr" type="text" value="4"> , <input onchange="stef();this.select()" onmouseover="this.select()" onkeypress="return ISKey1(event)" class="cstr" type="text" value="3"> ) = <nobr class="cstr"></nobr></td><td>TxT.substr( Start , Length ) Start 起始數第幾個字，Length 顯示幾多個字。</td></tr><!----------------------------------------------------------><td>TxT.substr ( <input onchange="stef();this.select()" onmouseover="this.select()" onkeypress="return ISKey1(event)" class="cstr" type="text" value="4"> , <input onchange="stef();this.select()" onmouseover="this.select()" onkeypress="return ISKey1(event)" class="cstr" type="text" value="3"> )= <nobr class="cstr"></nobr></td><td>TxT.substr( Start , Length ) Start 如果是負數從後數上第幾個字，Length 顯示幾多個字。</td></tr><!------------------------------------------------------------><td>TxT.substr ( <input onchange="stef();this.select()" onmouseover="this.select()" onkeypress="return ISKey1(event)" class="cstr" type="text" value="6"> )= <nobr class="cstr"></nobr></td><td>TxT.substr( Start , Length ) Start 起始數第幾個字，Length 如果不設定結尾位置當作最尾位元。</td></tr><!-----------------------------------------------------------><td>TxT.substring( <input onchange="stef();this.select()" onmouseover="this.select()" onkeypress="return ISKey1(event)" class="cstr" type="text" value="4"> , <input onchange="stef();this.select()" onmouseover="this.select()" onkeypress="return ISKey1(event)" class="cstr" type="text" value="8"> )= <nobr class="cstr"></nobr></td><td>TxT.substring( Start , End ) Start 起始數第幾個字開始，End 顯示到起始數第幾個字完。</td></tr><!-----------------------------------------------------------------><td>TxT.substring ( <input onchange="stef();this.select()" onmouseover="this.select()" onkeypress="return ISKey1(event)" class="cstr" type="text" value="4"> , <input onchange="stef();this.select()" onmouseover="this.select()" onkeypress="return ISKey1(event)" class="cstr" type="text" value="3"> )= <nobr class="cstr"></nobr></td><td>TxT.substring( Start , End ) 參數不可以是負數。</td></tr><!------------------------------------------------------------><td>TxT.indexOf ( <input onchange="stef();this.select()" onmouseover="this.select()" class="cstr" type="text" value="567"> )= <nobr class="cstr"></nobr></td><td>TxT.indexOf( 字元或單字, 檢索起始位置) ，字元或單字在字串中的出現的第一個位置。</td></tr><!-----------------------------------------------------------------><td>TxT.indexOf ( <input onchange="stef();this.select()" onmouseover="this.select()" class="cstr" type="text" value="135"> )= <nobr class="cstr"></nobr></td><td>TxT.indexOf( 字元或單字, 檢索起始位置) ，如果沒有找到，就返回 -1。</td></tr><!------------------------------------------------------------------><td>TxT.slice ( <input onchange="stef();this.select()" onmouseover="this.select()" onkeypress="return ISKey1(event)" class="cstr" type="text" value="5"> )= <nobr class="cstr"></nobr></td><td>TxT.slice( Start , End) ，Start 起始數第幾個字開始，End 顯示到起始數第幾個字完。</td></tr></tbody></table><br /> <script>function stef() { var TxT = "0123456789ABCDEF"; bb = document.getElementsByClassName("cstr"); bb[2].innerHTML = TxT.substr(bb[0].value,bb[1].value); bb[5].innerHTML = TxT.substr(bb[3].value,bb[4].value); bb[7].innerHTML = TxT.slice(bb[6].value); bb[10].innerHTML = TxT.substring(bb[8].value,bb[9].value); bb[13].innerHTML = TxT.substring(bb[11].value,bb[12].value); bb[15].innerHTML = TxT.indexOf(bb[14].value); bb[17].innerHTML = TxT.indexOf(bb[16].value); bb[19].innerHTML = TxT.slice(bb[18].value); bb[21].innerHTML = TxT.slice(bb[20].value); bb[24].innerHTML = TxT.slice(bb[22].value,bb[23].value); } stef(); </script> <script>function ISKey1(event){ var charCode = (event.which) ? event.which : event.keyCode; if (charCode == 13 ){ return true;}; if (charCode > 41 && charCode < 58){ return true;}; return false; } </script>

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<font size =6><pre> even 偶數 / odd 奇數 ？<br /><font size =6><input onchange="Even(this.value);this.select()" onmouseover="this.select()" onkeypress="return ISKey1(event)" type="text" value="4"> <br /><span id="Dp">input number</span><br /><br /><br />if (i % 2 === 0) { /* we are even */ } <br /> else { /* we are odd */ } <br /><br /><br /></pre> <script>function Even(xx) { var txt = "input number " + xx + " is " if (xx % 2 === 0) { txt += 'even 偶數' ; } else { txt += 'odd 奇數' ; } Dp.innerHTML= txt ; } function ISKey1(event){ var charCode = (event.which) ? event.which : event.keyCode; if (charCode == 13 ){ return true;}; if (charCode > 41 && charCode < 58){ return true;}; return false; } </script>

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<font size =6><pre> JavaScript replace() 方法 字符替換另一些字符<br /> <font size =5> g: 進行全局替換。 i:不分大小寫。<br /><br /> "123456123456".replace(/34/ ,"AB") ⇉ 12<font <br /> color="red">AB<font color="black">56123456<br /> "123456123456".replace(/34/<font color="red">g<font color="black">,"AB") ⇉ 12<font <br /> color="red">AB<font color="black">5612<font color="red">AB<font color="black">56<br /> "abcdabcd".replace(/AB/,"12") ⇉ abcdabcd<br /> "abcdabcd".replace(/AB/<font <br /> color="red">i,<font color="black">"12") ⇉ <font <br /> color="red">12<font color="black">cdabcd<br /> "abcdabcd".replace(/AB/<font <br /> color="red">ig<font color="black">,"12") ⇉ <font <br /> color="red">12<font color="black">cd<font <br /> color="red">12<font color="black">cd<br /><br /></pre>

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#文字 轉換 數字#html 文字 轉換 數字#val 轉換 數字#html #Math()#script Math() #string to number#script parseFloat()#script parseInt() #script #length()#script slice()#script substring()#script substr() #script even odd#script 偶數/奇數#script replace()#script 字符替換