How can I get a progress bar, when a block consists of one trial and that trial consists of 50 text elements?
I already constructed an rectangle and wanted to be its width depending on the number of the current element (1...50) divided by the number of text elements (50).
But how can I implement a value that shows the number of the current text element?

I don't understand what a "trial consisting of 50 text elements" means. Please post some actual code to illustrate.

<block WS>
/ trials = [1-6 = WS]
/ timeout = 420000
/ bgstim = (BG1)
</block>

<trial WS>
/ stimulusframes = [1 = WS]
/ validresponse = ("f", "g", "h", "j", "k")
</trial>

<text WSF>
/ items = WSF
/ select = sequence (1,2,3,4,5,6)
/ position = (50%, 30%)
</text>

<item WSF>
/1 = "Wort1"
/2 = "Wort2"
/3 = "Wort3"
/4 = "Wort4"
/5 = "Wort5"
/6 = "Wort6"
</item>