JavaScript基本语法

1. 创建脚本块
2. <scriptlanguage=”JavaScript”>
3. JavaScriptcodegoeshere
4. </script>
5. 隐藏脚本代码
7. <scriptlanguage=”JavaScript”>
8. <!--
9. document.write(“Hello”);
10. //-->
11. </script>
13. 浏览器不支持的时候显示
15. <noscript>
16. Hellotothenon-JavaScriptbrowser.
17. </noscript>
19. 链接外部脚本文件
21. <scriptlanguage=”JavaScript”src="/”youname.js"”></script>
23. 注释脚本
25. //Thisisacomment
26. document.write(“Hello”);//Thisisacomment
27. /*
28. Allofthis
29. isacomment
30. */
32. 输出到浏览器
34. document.write(“<strong>输出内容</strong>”);
36. 定义变量
38. varmyVariable=“somevalue”;
40. 字符串相加
42. varmyString=“String1”+“String2”;
44. 字符串搜索
46. <scriptlanguage=”JavaScript”>
47. <!--
48. varmyVariable=“Hellothere”;
49. vartherePlace=myVariable.search(“there”);
50. document.write(therePlace);
51. //-->
52. </script>
54. 字符串替换
56. thisVar.replace(“Monday”,”Friday”);
58. 格式化字串
60. <scriptlanguage=”JavaScript”>
61. <!--
62. varmyVariable=“Hellothere”;
63. document.write(myVariable.big()+“<br>”);
64. document.write(myVariable.blink()+“<br>”);
65. document.write(myVariable.bold()+“<br>”);
66. document.write(myVariable.fixed()+“<br>”);
67. document.write(myVariable.fontcolor(“red”)+“<br>”);
68. document.write(myVariable.fontsize(“18pt”)+“<br>”);
69. document.write(myVariable.italics()+“<br>”);
70. document.write(myVariable.small()+“<br>”);
71. document.write(myVariable.strike()+“<br>”);
72. document.write(myVariable.sub()+“<br>”);
73. document.write(myVariable.sup()+“<br>”);
74. document.write(myVariable.toLowerCase()+“<br>”);
75. document.write(myVariable.toUpperCase()+“<br>”);
76. varfirstString=“MyString”;
77. varfinalString=firstString.bold().toLowerCase().fontcolor(“red”);
78. //-->
79. </script>
81. 创建数组
83. <scriptlanguage=”JavaScript”>
84. <!--
85. varmyArray=newArray(5);
86. myArray[0]=“FirstEntry”;
87. myArray[1]=“SecondEntry”;
88. myArray[2]=“ThirdEntry”;
89. myArray[3]=“FourthEntry”;
90. myArray[4]=“FifthEntry”;
91. varanotherArray=newArray(“FirstEntry”,”SecondEntry”,”ThirdEntry”,”FourthEntry”,”FifthEntry”);
92. //-->
93. </script>
95. 数组排序
97. <scriptlanguage=”JavaScript”>
98. <!--
99. varmyArray=newArray(5);
100. myArray[0]=“z”;
101. myArray[1]=“c”;
102. myArray[2]=“d”;
103. myArray[3]=“a”;
104. myArray[4]=“q”;
105. document.write(myArray.sort());
106. //-->
107. </script>
109. 分割字符串
111. <scriptlanguage=”JavaScript”>
112. <!--
113. varmyVariable=“a,b,c,d”;
114. varstringArray=myVariable.split(“,”);
115. document.write(stringArray[0]);
116. document.write(stringArray[1]);
117. document.write(stringArray[2]);
118. document.write(stringArray[3]);
119. //-->
120. </script>
122. 弹出警告信息
124. <scriptlanguage=”JavaScript”>
125. <!--
126. window.alert(“Hello”);
127. //-->
128. </script>
130. 弹出确认框
132. <scriptlanguage=”JavaScript”>
133. <!--
134. varresult=window.confirm(“ClickOKtocontinue”);
135. //-->
136. </script>
138. 定义函数
140. <scriptlanguage=”JavaScript”>
141. <!--
142. functionmultiple(number1,number2){
143. varresult=number1*number2;
144. returnresult;
145. }
146. //-->
147. </script>
149. 调用JS函数
151. <ahref=”#”onClick=”functionName()”>Linktext</a>
152. <ahref="/”javascript:functionName"()”>Linktext</a>
154. 在页面加载完成后执行函数
156. <bodyonLoad=”functionName();”>
157. Bodyofthepage
158. </body>
160. 条件判断
162. <script>
163. <!--
164. varuserChoice=window.confirm(“ChooseOKorCancel”);
165. varresult=(userChoice==true)?“OK”:“Cancel”;
166. document.write(result);
167. //-->
168. </script>
170. 指定次数循环
172. <script>
173. <!--
174. varmyArray=newArray(3);
175. myArray[0]=“Item0”;
176. myArray[1]=“Item1”;
177. myArray[2]=“Item2”;
178. for(i=0;i<myArray.length;i++){
179. document.write(myArray+“<br>”);
180. }
181. //-->
182. </script>
184. 设定将来执行
186. <script>
187. <!--
188. functionhello(){
189. window.alert(“Hello”);
190. }
191. window.setTimeout(“hello()”,5000);
192. //-->
193. </script>
195. 定时执行函数
197. <script>
198. <!--
199. functionhello(){
200. window.alert(“Hello”);
201. window.setTimeout(“hello()”,5000);
202. }
203. window.setTimeout(“hello()”,5000);
204. //-->
205. </script>
207. 取消定时执行
209. <script>
210. <!--
211. functionhello(){
212. window.alert(“Hello”);
213. }
214. varmyTimeout=window.setTimeout(“hello()”,5000);
215. window.clearTimeout(myTimeout);
216. //-->
217. </script>
219. 在页面卸载时候执行函数
220. <bodyonUnload=”functionName();”>
221. Bodyofthepage
222. </body>