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JavaScript - Slice() In Js Help Please
i have in my JS:
Code: function viewornot(blocked_status)
{
alert(blocked_status);
var id = blocked_status.slice(0,"/");
}
where blocked_status consists of two parts part one is the id of the user part to is "/0" so a typical value of blocked_status = 63/0 63 is the id id can grow from being 1 digit to x digits as users grow how can i get whatever is in front of the "/" thus the id please??? thank you Similar TutorialsI am relatively new to JS and was wondering what would be the best way of creating a colurful pie chart that produces a text and picture box when the cursor goes over a particular pie chart 'slice' (i.e. a different text/picture box for each 'slice')? Im not looking for someone to do all the work for me, I am enjoying the programming so far, but if someone could point me in the right direction? I have access to Dreamweaver CS6 and Fireworks CS5 if they could be of any help? Code: <html>
<head>
<title>Variable - Examples 1</title>
<script type="text/javascript">
function Student(firstName, lastName, email, courseID, titleArray, pointsArray){
this.firstName = firstName;
this.lastName = lastName;
this.email = email;
this.courseID = courseID;
this.title = titleArray;
this.points = pointsArray;
this.assign = this.points.slice(0,4);
this.exams = this.points.slice(-2);
this.assignments = function() { return task(this.title,this.points); }
this.totalPoints = function() {return addExam(this.assign,this.exams); }
this.finalGrade = calcGrade;
}
Student.prototype = {
constructor : Student,
toString : studentInfo
};
//assign and exam doesn't seem to hold no values inside.. ???
function addExam(assign,exams){
var exams=this.exams;
var high1=exams[0];
var high2=0;
while(high2<exams.length){
high1=Math.max(high1,exams[high2]);
high2++;
}
var sum = 0;
for (var i=0; i < assign.length; i++){
sum += assign[i];
}
return sum + high1;
}
var totalPoints = addExam();
function calcGrade(){
var grade;
if (totalPoints >= 190){
return "A+";
}else if (totalPoints >= 180){
return "A";
}else if (totalPoints >= 175){
return "B+"
}else if (totalPoints >= 170){
return "B";
}else if (totalPoints >= 165){
return "B-";
}else if (totalPoints >= 160){
return "C";
}else if (totalPoints >= 150){
return "D";
}else if (totalPoints < 150){
return "F";
}
}
function studentInfo(){
return "Student : " + this.lastName + "," + this.firstName + "<br>"+ "eMail : " + this.email + "<br>" + "Course ID : " + this.courseID + "<br>" + "--------------------------------" + "<br>" + this.assignments() + "--------------------------------" + "<br>" + "Total Points : " + this.totalPoints() + "<br>" + "Final Grade : " + this.finalGrade();
}
function createStudents(){
var student1 = new Student("Jake", "Hennry", "jhennery@gmail.com","COIN-070B.01", ["Assignment1","Assignment2","Assignment3","Assignment4","Assignment5","MidTerm", "Final"], [25, 25, 28, 20, 29, 40, 40] );
alert("Student : " + student1.lastName + "," + student1.firstName + "\n"+ "eMail : " + student1.email + "\n" + "Course ID : " + student1.courseID + "\n" + "---------------------------------------" + "\n" + student1.assignments() + "\n" + "---------------------------------------" + "\n" + "Total Points : " + student1.totalPoints() + "\n" + "Final Grade : " + student1.finalGrade());
}
var titleArray = ["Assignment1","Assignment2","Assignment3","Assignment4","Assignment5","MidTerm", "Final"];
var pointsArray = [30, 30, 28, 27, 29, 41, 45];
var student = new Student("Haripriyaa", "Ganesan", "haripriyaa@gmail.com","COIN-070B.01", titleArray, pointsArray );
</script>
</head>
<body>
<script type="text/javascript">
document.writeln(student.toString());
</script>
</body>
</html>
Why is the callwhy is the slice method only a method of an Array instance? The reason why I ask is because if you want to use it for the arguments property of function object, or a string, or an object, or a number instance, you are forced to use Array.prototype.slice.call(). And by doing that, you can pass in any type of object instance (Array, Number, String, Object) into it. So why not just default it as a method of all object instances built into the language? In other words, instead of doing this: Code: function Core(){
var obj = {a : 'a', b : 'b'};
var num = 1;
var string = 'aff';
console.log(typeof arguments);//Object
console.log(arguments instanceof Array);//false
var args1 = Array.prototype.slice.call(arguments);
console.log(args1);
var args2 = Array.prototype.slice.call(obj);
console.log(args2);
var args3 = Array.prototype.slice.call(num);
console.log(args3);
var args4 = Array.prototype.slice.call(string);
console.log(args4);
Core('dom','event','ajax');
Why not just be able to do this: Code: function Core(){
var obj = {a : 'a', b : 'b'};
var num = 1;
var string = 'aff';
var args = arguments.slice(0);
var args2 = obj.slice(0);
var args3 = num.slice(0);
var args4 = string.slice(0);
//right now none of the above would work but it's more convenient than using the call alternative.
}
Core('dom','event','ajax');
Why did the designers of the javascript scripting language make this decision? Thanks for response. |
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