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Javascript Reference Guide
 
 
This guide contains useful Javascript tips.

Quick guides







Local and global variables.



Information


Variables with the keyword var are local variables.
Variables without keyword var are global variables.

Examples 
<script type="text/javascript" language="JavaScript">

a = 1;

jsxDisplay();

function jsxDisplay() {
   a = 2;
   // Value a inside the function =2
   alert("Value a inside the function =" + a);
}

// Value of a outside the function = 2
alert("Value of a outside the function =" + a);
</script>
Show demo




<script type="text/javascript" language="JavaScript">

var a = 1;

jsxDisplay();

function jsxDisplay() {
   a = 2;
   // Value a inside the function = 2
   alert("Value a inside the function =" + a);
}

// Value of a outside the function = 2
alert("Value of a outside the function =" + a);
</script>
Show demo




<script type="text/javascript" language="JavaScript">

a = 1;

jsxDisplay();

function jsxDisplay() {
   var a = 2;
   b = 10;
   // Inside the function a=2, b=10
   alert("Inside the function a="+a+", b="+b);
}

alert("Outside the function a="+a); // Outside the function a=1
alert("Outside the function b="+b); // Outside the function b=10
</script>
Show demo




<script type="text/javascript" language="JavaScript">

var a = 1;

jsxDisplay();

function jsxDisplay() {
   var a = 2;
   var b = 10;
   // Inside the function a=2, b=10
   alert("Inside the function a="+a+", b="+b);
}

alert("Outside the function a="+a); // Outside the function a=1
alert("Outside the function b="+b); // Error b is undefined
</script>
Show demo