JavaScript精簡學習1:基礎知識

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javascript

  有些時候你精通一門語言,但是會發現你其實整天在和其它語言打交道,也許你以為這些微不足道,不至於影響你的開發進度,但恰恰是這些你不重視的東西會浪費你很多時間,我一直以為我早在幾年前就已經精通JavaScript了,直到目前,我才越來越覺得JavaScript 遠比我想象的複雜和強大,我開始崇拜它,就像崇拜所有OOP語言一樣~

  趁著節日的空隙,把有關JavaScript的方法和技巧整理下,讓每個在為JavaScript而煩惱的人明白,JavaScript就這麼回事!並希望JavaScript還可以成為你的朋友,讓你豁然開朗,在項目中更好的應用~

  適合閱讀範圍:對JavaScript一無所知~離精通只差一步之遙的人

  基礎知識:HTML

1 建立指令碼塊
1: <script language=”JavaScript”>
2: JavaScript code goes here
3: </script>


2 隱藏指令碼代碼
1: <script language=”JavaScript”>
2: <!--
3: document.write(“Hello”);
4: // -->
5: </script>

在不支援JavaScript的瀏覽器中將不執行相關代碼

3 瀏覽器不支援的時候顯示
1: <noscript>
2: Hello to the non-JavaScript browser.
3: </noscript>


4 連結外部指令檔
1: <script language=”JavaScript” src=”filename.js”></script>


5 注釋指令碼
1: // This is a comment
2: document.write(“Hello”); // This is a comment
3: /*
4: All of this
5: is a comment
6: */


6 輸出到瀏覽器
1: document.write(“<strong>Hello</strong>”);


7 定義變數
1: var myVariable = “some value”;


8 字串相加
1: var myString = “String1” + “String2”;


9 字串搜尋
1: <script language=”JavaScript”>
2: <!--
3: var myVariable = “Hello there”;
4: var therePlace = myVariable.search(“there”);
5: document.write(therePlace);
6: // -->
7: </script>


10 字串替換
1: thisVar.replace(“Monday”,”Friday”);


11 格式化字串
1: <script language=”JavaScript”>
2: <!--
3: var myVariable = “Hello there”;
4: document.write(myVariable.big() + “<br>”);
5: document.write(myVariable.blink() + “<br>”);
6: document.write(myVariable.bold() + “<br>”);
7: document.write(myVariable.fixed() + “<br>”);
8: document.write(myVariable.fontcolor(“red”) + “<br>”);
9: document.write(myVariable.fontsize(“18pt”) + “<br>”);
10: document.write(myVariable.italics() + “<br>”);
11: document.write(myVariable.small() + “<br>”);
12: document.write(myVariable.strike() + “<br>”);
13: document.write(myVariable.sub() + “<br>”);
14: document.write(myVariable.sup() + “<br>”);
15: document.write(myVariable.toLowerCase() + “<br>”);
16: document.write(myVariable.toUpperCase() + “<br>”);
17:
18: var firstString = “My String”;
19: var finalString = firstString.bold().toLowerCase().fontcolor(“red”);
20: // -->
21: </script>


12 建立數組
1: <script language=”JavaScript”>
2: <!--
3: var myArray = new Array(5);
4: myArray[0] = “First Entry”;
5: myArray[1] = “Second Entry”;
6: myArray[2] = “Third Entry”;
7: myArray[3] = “Fourth Entry”;
8: myArray[4] = “Fifth Entry”;
9: var anotherArray = new Array(“First Entry”,”Second Entry”,”Third Entry”,”Fourth Entry”,”Fifth Entry”);
10: // -->
11: </script>


13 數組排序
1: <script language=”JavaScript”>
2: <!--
3: var myArray = new Array(5);
4: myArray[0] = “z”;
5: myArray[1] = “c”;
6: myArray[2] = “d”;
7: myArray[3] = “a”;
8: myArray[4] = “q”;
9: document.write(myArray.sort());
10: // -->
11: </script>


14 分割字串
1: <script language=”JavaScript”>
2: <!--
3: var myVariable = “a,b,c,d”;
4: var stringArray = myVariable.split(“,”);
5: document.write(stringArray[0]);
6: document.write(stringArray[1]);
7: document.write(stringArray[2]);
8: document.write(stringArray[3]);
9: // -->
10: </script>


15 彈出警告資訊
1: <script language=”JavaScript”>
2: <!--
3: window.alert(“Hello”);
4: // -->
5: </script>


16 彈出確認框
1: <script language=”JavaScript”>
2: <!--
3: var result = window.confirm(“Click OK to continue”);
4: // -->
5: </script>


17 定義函數
1: <script language=”JavaScript”>
2: <!--
3: function multiple(number1,number2) {
4: var result = number1 * number2;
5: return result;
6: }
7: // -->
8: </script>


18 調用JS函數
1: <a href=”#” onClick=”functionName()”>Link text</a>
2: <a href=”javascript:functionName()”>Link text</a>


19 在頁面載入完成後執行函數
1: <body onLoad=”functionName();”>
2: Body of the page
3: </body>


20 條件判斷
1: <script>
2: <!--
3: var userChoice = window.confirm(“Choose OK or Cancel”);
4: var result = (userChoice == true) ? “OK” : “Cancel”;
5: document.write(result);
6: // -->
7: </script>


21 指定次數迴圈
1: <script>
2: <!--
3: var myArray = new Array(3);
4: myArray[0] = “Item 0”;
5: myArray[1] = “Item 1”;
6: myArray[2] = “Item 2”;
7: for (i = 0; i < myArray.length; i++) {
8: document.write(myArray + “<br>”);
9: }
10: // -->
11: </script>


22 設定將來執行
1: <script>
2: <!--
3: function hello() {
4: window.alert(“Hello”);
5: }
6: window.setTimeout(“hello()”,5000);
7: // -->
8: </script>


23 定時執行函數
1: <script>
2: <!--
3: function hello() {
4: window.alert(“Hello”);
5: window.setTimeout(“hello()”,5000);
6: }
7: window.setTimeout(“hello()”,5000);
8: // -->
9: </script>


24 取消定時執行
1: <script>
2: <!--
3: function hello() {
4: window.alert(“Hello”);
5: }
6: var myTimeout = window.setTimeout(“hello()”,5000);
7: window.clearTimeout(myTimeout);
8: // -->
9: </script>


25 在頁面卸載時候執行函數
1: <body onUnload=”functionName();”>
2: Body of the page
3: </body>



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