Usage of eval in JavaScript / eval

Convert String to JavaScript Variable / Method

     eval() is JavaScript methods to use convert the string to variable, this will help in many situation, in the following situation we can use this.

Case 1

     Some time the variable is stored into value, in this situation we can convert it to variable.
Example
1

var test="count";
var count=100;
alert(eval(test)); //100

2

var arr=["var1","var2","var3","var4","var5"];

var var1="Value1";
var var2="Value2";
var var3="Value3";
var var4="Value4";
var var5="Value5";

for(i=0;i<arr.length;i++)
{
  alert(eval(arr[i]));
}


Output:
Value1
Value2
Value3
Value4
Value5

Case 2

     If we want to use the replace JavaScript method like below you should need the eval() help.
Example

var chr="a";
alert(  ("abababab").replace(/chr/g,"L")  );

Output:

abababab

     In the above situation chr will consider as string, but in there we need to assign variable. So we can use the eval() like below example.

var chr="a";

alert(  eval("('abababab').replace(/"+chr+"/g,'L')")   );



Output:

LbLbLbLb

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