JavaScript Calculator Web version implementation code sharing _javascript tips

JavaScript Web calculator code, which is written in DW!
HTML Chapter

CSS Chapter

@charset "Utf-8";
* * CSS Document

//. TRB {
 Font-family:georgia, "Times New Roman", times, serif;
 font-size:24px;
 Color: #FFF;
 Background-color: #333;
 Text-align:center;
 border:1px solid #999;
operator {
 background-color: #333;
 font-size:18px;
 Color: #C60;
 Font-family:verdana, Geneva, Sans-serif;
td:hover{ 
 font-size:28px;
 Cursor:pointer 
}
. TXT {
 height:100px;
 width:320px;
 Background-color: #333;
 Text-align:left;
 Vertical-align:bottom;
 Color: #FFF;
 font-size:30px;
}

JavaScript posts

 Implement calculator function//result var = 0;
The number in the Display box (default is "0") var screennum = "0";
The initial input state of the number, the default is 0, and when any operator key is pressed, the input status of the number becomes 1 var state = 0;
Prevent repeating by operation keys var avoidrepeat = true;

Operation Keys (default is 0--equals number) var operator = 0;
 Step one: Get the key value and display the function command (num) {//Get the Display box value var str = String (document.form1.txt.value) in the Display box; The value is judged, if the value is not "0", and enter state 0, then return the former, otherwise "" (double three mesh operation)//Two judgment conditions: 1, the Display box value is "0", 2, the number of input state str = (str!= "0")?
 (state = = 0) (str: ""): "";
 Append character to current value str = str + String (num);
 Refresh display document.form1.txt.value = str;
 After pressing any number key, the input status of the number becomes 0 state = 0;
Reset prevent repeat key avoidrepeat = true;
 //Step Two: Make sure that the number you enter is legitimate, with at most a small number of decimal points function dot () {var str = String (document.form1.txt.value);
 If the number is not preceded by an operator, the previous value is returned, otherwise, "0"; str = (state = = 0)? str: "0"; In Java, string has a length () method, and JS string has the Length property for (i=0;i<=str.length;i++) {//substr () gets subscript starting from I, the number of 1 substring if ( Str.substr (i,1) = = ".")
 {//When decimal is present, the program terminates return;
 }///If no decimal point, then add str = str+ "." After the number;
 Refresh display document.form1.txt.value = str;
 
Initial input state = 0 of the number of restores; }

Step three: Process the BACKSPACE function Backspace () {var str= String (Document.form1.txt.value);
 If the number in the display box is not equal to "0", return str, or return "str = (str!=" 0 ")? Str:" ";
 Gets substring str = STR.SUBSTR (0,str.length-1);
 If STR is not "", return substring str, otherwise str= "0" str = (str!= "")? Str: "0";
 
Refresh display document.form1.txt.value = str;
 //Step Fourth: Delete all function DeleteAll () {//Display box set to "0" Document.form1.txt.value = "0";
 Initial input state = 0 of the number of restores;
Recovery operator key, default is 0--equals number operator = 0;
 //Step Fifth: addition function Add () {//Call compute function Calculate ();
 Change the input status of number state = 1;
 
Change operator key, 1--plus operator = 1;
 //Step Sixth: Subtraction function subtract () {//Call compute function Calculate ();
 Change the input status of number state = 1;
 
 
2--minus operator = 2;
 //Step Seventh: Multiplication function multiply () {//Call compute function Calculate ();
 Change the input status of number state = 1;
 
3--multiplication operator = 3;
 //Step Eighth: Division function divide () {//Call compute function Calculate ();
 Change the input status of number state = 1;
 
4--division operator = 4;
 //Step Nineth: Positive and negative function sign () {//5--plus sign operator = 5;
 Call the calculation function calculate ();
 Change the input status of number state = 1;
 0--equals number operator = 0; The positive sign can be continuousPress Avoidrepeat = true;
 }//Step tenth: equals function equal () {//Call compute function Calculate ();
 Change the input status of number state = 1;
 
 
0--equals number operator = 0;
 //Step 11th: Compute function Calculate () {//Get the value Screennum = number (Document.form1.txt.value) in the Display box;
  if (avoidrepeat) {switch (operator) {case 1:result = result + Screennum;
  Document.form1.txt.value = result;
  Break
  Case 2:result = Result-screennum;
  Document.form1.txt.value = result;
  Break
  Case 3:result = result * SCREENNUM;
  Document.form1.txt.value = result;
  Break
   Case 4:if (Screennum = = 0) {//Set the value of the Display box document.getElementById ("TXT"). value= "Divisor cannot be 0";
  After 3s, perform clear screen function settimeout (clearscreen,3000);
   }else{result = Result/screennum;
  Document.form1.txt.value = result;
  } break;
  Case 5:result = ( -1) *screennum;
  Document.form1.txt.value = result;
  Break
  Case 0:result = Screennum;
  Document.form1.txt.value = result;
  
 Break
 ///When the operator key is pressed, Avoidrepeat = False can no longer be pressed; }//Step 12th: Clear screen functions function CleaRscreen () {document.getElementById ("TXT"). Value = "0";

 }

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