I have question on this Javascript code. i am a basic learner. The books says that they need to assign the PurcahsePrice to 0 as they do not know what the purchase price is as they need the customer to key in the purchase price ( that is why the prompt command exist) My question is , since the PurchasePrice = 0 is being replace by another value when the customer is keying in a new value to it ( at the prompt), Can i use values other than 0, i mean since the 0 value is gonna be replaced, i can use like 5, 34, or other values. Can i do that? if not, why not? Thanks.
yeah you can definitely assign any number to that variable coz var PurchasePrice = 0; only means that you declare a variable and assign an initial value to it.
That means in order to declare a variable, you MUST assign an initial value to it first. I got to do that for every situation? i cannot do this? : ( i have seen in example in books that they do that)
not it does not. javascript is so very versatile... i have seen examples of really bad variable assignment, including in so called tutorials. things like pre-declaring the number of items you will have in an array (eg, var blah = new Array(30); ) so if you are going to use this within the scope of the same function/context why bother with the extra line and assignment? var PurchasePrice = prompt('Please enter your purchase price'. ''); it only makes sense to declare variables if they need to be accessible throughout from functions / classes as global (or even local to the functions) this would all be a valid way in declaring variables: var foo, bar, moo = 43, messageUser = function(what) { alert("The answer to "+what+" is "+moo); }, items = [], myobject = {}, myobject2 = { html: "bar", styles: { border: "1 px solid #000", padding: 2 }, className: "myWindow", className2: "myWindowFocused", events: { "onmouseover": function() { this.className = myobject2.className2; }, "onmouseout": function() { this.className = myobject2.className; } } }; // end variable declarations... PHP: