javascript - 我试图为内置 javascript 函数（大写）编写代码。这有帮助吗？

Question

这段代码基本上用作javascript touppercase shortformat的内置函数，这对面试很有帮助。有时我们不需要使用内置函数..所以有它们的代码。

    //change lower case to upper case
    function Change_Upper_Case() {
    var a1 = [], a6 = [], i = 0; // define all variables
    a1 = document.getElementById('EnterString').value; //get value which is    enter by you
    while(i < a1.length) { //check condition is true or false
        var a2 = a1[i]; 
       var a3 = a2.charCodeAt(0); //get ASCII value of char in number format
       var a5 = a2;
   if(a3 >= 97 && a3 < 123) { // a = 97 and z=122
    var a4 = a3-32;
    a5 = String.fromCharCode(a4); //change ASCII value of a4 in char format
    }
    a6[i] = a5;
    i++;
    }
    document.getElementById('ShowString').innerHTML = a6.join(''); //print input String on your browser  
}

   

 //change lower case to upper case
    function Change_Upper_Case() {
    	var a1 = [], a6 = [], i = 0; // define all variables
    	a1 = document.getElementById('EnterString').value; //get value which is enter by you
    while(i < a1.length) { //check condition is true or false
    	var a2 = a1[i]; 
    	var a3 = a2.charCodeAt(0); //get ASCII value of char in number format
    	var a5 = a2;
    if(a3 >= 97 && a3 < 123) { // a = 97 and z=122
    	var a4 = a3-32;
    	a5 = String.fromCharCode(a4); //change ASCII value of a4 in char format
    	}
    	a6[i] = a5;
    	i++;
    	}
    	document.getElementById('ShowString').innerHTML = a6.join(''); //print input String on your browser  
    }

   

 <input type="text" id="EnterString"/>
    <input type="button" value="Upper Case" onclick="Change_Upper_Case()"/>
    <span id="ShowString"></span><br/>

Answer 1

Javascript 已经有一个字符串类型的 toUpperCase 函数，看看http://www.w3schools.com/jsref/jsref_touppercase.asp