What are the ways to call functions in javascript

Methods for calling functions in JavaScript: 1. Use the "Object.Function Name()" statement to call; 2. Use "Function Name().call(Caller, Parameter 1, Parameter 2, ... ..);" statement call; 3. Use the "function name().apply(caller, parameter array);" statement call.

The operating environment of this tutorial: Windows 7 system, JavaScript version 1.8.5, Dell G3 computer.

Three ways to implement functions

Named functions

		<script type="text/javascript">
		function show(name){
			document.write(name+"  hellow")
		}
		show(&#39;laoli&#39;);
		</script>

Anonymous function (recommended)

		<script type="text/javascript">
			
		var f=function(name){
			document.write(&#39;name+"  hellow")
		}
		f(&#39;laoli&#39;);
		</script>

Use the function class to construct an anonymous function

Format: new Function (('Parameter list'), ('Parameter list'), ('Function execution body'));

Note:

• Function has a capital letter
• Parameter lists and function execution bodies should be enclosed in quotation marks
• End with a semicolon

		<script type="text/javascript">
			var f = new Function(&#39;name&#39;, &#39;alert(name+"你好");&#39;);
			f(&#39;laoli&#39;);
		</script>

Column: Use of named functions

		<script type="text/javascript">
			function show(){
				document.write(&#39;我是命名函数&#39;)
			}
			var f=show();
			f();//函数调用
		</script>

Variables and function access in functions

Global variables in functions can be accessed directly

Functions in functions need to be called first before they can be accessed

Column: Implement function calls within functions (calls of local functions)

		<script type="text/javascript">
		var num=&#39;laoli&#39;;
		var f=function(num){
			document.write(num+&#39;真可爱&#39;);
			
			function show(){
				document.write(&#39;他不是女人&#39;)
			}
			show();//调用show(）函数
		}
		//执行函数
		f(num);
		</script>

Result: Laoli is so cute, he is not a woman

Three ways to call functions

• Object.Function application
• call method calls functionFunction application.(caller,parameter 1, parameter 2, .....)
• apply method calls the function apply(caller, parameter array)

##Note: When Declare a function that is assigned to the window object by default

Column: implement three calls

		<script type="text/javascript">
			//创建命名函数
			function show(name, age) {
				document.write(name + &#39;是男人，他&#39; + age + &#39;岁&#39;);
			}
			//对象.函数应用
			window.show(&#39;小明&#39;, &#39;30&#39;); 
			//all方法调用函数 函数应用.( 调用者,参数1 ,参数2 , .....)
			show.call(window, &#39;小明&#39;, &#39;30&#39;);
			//apply方法调用函数  apply(调用者,参数数组)
			show.apply(window, [&#39;小明&#39;, &#39;30&#39;]);
		</script>

Column: in the array Function call

		<script type="text/javascript">
			//show传入两个参数 1个数组 1个函数
			function show(arr, func) {
				//func.call(window, arr);
				func.apply(window, [arr])
			}
			show([1, 2, 3, 4], function(arr) {
				for (i in arr) {
					document.write(arr[i] + &#39;<br/>&#39;)
				}
			});
		</script>

Result:

[Related recommendations:

javascript learning tutorial]

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