1.通过内置方法 arguments

   function sum(){
    
    
	   let count = 0
    for(let i = 0 ; i < arguments.length ; i++){
    
    
      if(isNaN(arguments[i])){
    
    
		  continue
	  }
	  else{
    
    
		  arguments[i] = Number(arguments[i])
		  count = arguments[i]+ count
	  }n 
	}
	return count
   }
   sum(1,1,1,1,1)
   
   console.log(sum(1,2,3,5,'ww',5,'7'));

2.ES6 新增语法 …args 运算符

function sum(...args) {
    
      //es6  变为数值的形式
			let count = 0
			for (let i = 0; i < args.length; i++) {
    
    

				if (isNaN(args[i])) {
    
    
                          continue
				} 
				else {
    
    

					args[i] = Number(args[i])

					count = args[i] + count
				}
				
			}
			return count
		}
		sum(1, 1, 1, 1, 1)
		console.log(sum(1, 2, 3, 5, 'ww', 5, '7'));